Most people who started their comic collection journey hardly ever thought about stuff like relative humidity and keeping their collection safe before purchasing their first issue. We got into them for the stories, the art, the thrill of finally tracking down that one back issue. But somewhere along the way, a stack of favourites turns into a proper collection, and a collection, whether you like the word or not, is an investment that deserves better than simply being shoved in a box under the bed.

The tricky part is that comic book damage is sneaky. It doesn’t happen overnight since it’s more of a slow creep caused by heat, damp, light and a handful of unwelcome creepy-crawlies, all working quietly in the background. By the time you notice the yellowing or the curling corners, the damage is usually already done, and there’s no undoing it.

The good news is that none of this is complicated once you understand what’s causing the problem. Read on as we walk you through exactly why comics deteriorate, and what you can do to stop it happening to yours.

Why Comic Books Deteriorate Over Time

The root of the issue is that comic book paper was never built to last. Publishers used cheap, acidic pulp stock because comics were meant to be read once and binned, not kept for sixty years in a protective sleeve. That inherent instability means comic paper reacts far more dramatically to its surroundings than, say, a hardback novel or a photograph.

Four things do almost all of the damage: heat and humidity, light, pests, and, surprisingly, the very materials you store your comics in, if they’re not the right ones. Get a handle on those four and you’ve solved most of the problem. Let’s tackle them one at a time.

What’s the Ideal Temperature and Humidity for Storing Comic Books?

If you only remember one fact from this article, make it this: aim for somewhere around 15–21°C (60–70°F) with relative humidity sitting between 40% and 50%. Storage that is too damp inevitably invites mould, warping and that unmistakable musty smell. In contrast, if it is too dry, the pages turn brittle and become prone to cracking.

Do note that consistency in these two factors matters more than hitting an exact figure. A room that swings wildly between muggy and bone-dry over the course of a day is far worse than one that sits at a slightly-off-but-stable level, because it’s the expansion and contraction of the paper fibres that causes the real long-term wear.

This is exactly why basements and attics have such a bad reputation among collectors—they’re notorious for temperature and humidity swings, and they carry the added risk of flooding or damp problems you might not spot until it’s too late. A spare room, a closet on the main level of the house, or a proper climate-controlled storage unit will all serve you far better than anywhere near the boiler or the roofline.

How Sunlight Damages Comic Books

Direct sunlight is one of the fastest ways to ruin a cover. UV exposure fades ink and weakens the paper fibres underneath, and unlike a spilled drink, there’s no cleaning it off afterwards. Once the colour’s gone, it’s gone for good.

It’s not just harsh, direct sun you need to worry about either. Ambient light from a window across the room, or even fluorescent bulbs left on for hours a day add up over months and years. The fix for this is simple: keep comics in closed boxes, opaque bins, or a cabinet with the door shut, rather than out on open shelving where they catch daylight. 

If you’ve got prized issues you want to actually display, UV-filtering sleeves or glazing are worth the extra spend, and rotating what’s on show helps spread the exposure around rather than letting one lucky (or unlucky) issue take all the punishment.

What Pests Eat Comic Books, and How Do You Keep Them Out?

Nobody wants to think about bugs getting into their collection, but it happens more than people realise. The main culprit is the silverfish, which is a small, silvery insect that’s drawn to the starch in paper and the glue used in bindings. Booklice can also cause similar surface damage on a smaller scale. Left unchecked, both will happily graze away at your comics for years without you noticing.

As such, it’s vital to spot an infestation early. Keep an eye out for faint yellow staining or tiny pepper-like specks around the edges of pages since that’s usually your first sign that something’s been nibbling. The good news is that the same advice from the previous section does double duty here: silverfish are drawn to moisture above almost anything else, so a damp room is basically an open invitation.

Keep humidity in check and you’ve already removed most of the risk. One extra tip worth knowing: silverfish prefer dark, undisturbed spaces, so a storage area with a bit of ambient light can actually help deter them. Just make sure it’s room light, not light falling directly onto the comics themselves since that circles back to the sun damage problem above.

Essential Supplies for Storing Comic Books Properly

You don’t need to spend a fortune here, but three things are genuinely non-negotiable: a protective bag, a backing board, and a proper storage box. Everything else is optional extras.

• Bags come in three main flavours. Polypropylene is the cheapest and most common and they’re perfectly fine for short-term use, but they break down and cloud over fairly quickly. Polyethylene is a step up, generally lasting seven or eight years before it needs replacing. Mylar sits at the top of the pile: it’s acid-free, chemically stable, and can protect a comic for decades without yellowing, stretching or shrinking. The catch is that it’s pricier and stiffer to work with, which is why most collectors reserve it for their more valuable or sentimental issues rather than the entire collection.
• Backing boards matter more than people think. Not every board labelled “acid-free” actually deserves the label because a lot of cheaper boards are only coated on the surface and lose that protection over time. The boards worth trusting have a calcium carbonate buffer running right through them, not just sprayed on top, which keeps them properly neutral for the long haul. Beyond the chemistry, boards also do a simple physical job: they keep the comic rigid so it doesn’t bend or crease inside the bag.
• Boxes are your final layer. Traditional cardboard short and long boxes do the job well, though acid-free plastic bins offer better resistance to moisture. If you’re on a budget, tier your protection: cheaper poly bags and standard boards for everyday reading copies, and the Mylar-and-buffered-board combination for the issues that actually warrant it. No need to gold-plate the whole collection if only a handful of books carry real value.

Best Practices for Packing a Comic Book Storage Box

Packing is the part collectors get wrong most often. The golden rule is to store comics upright, packed firmly enough that they can’t lean, slump or topple over, but never so tightly that you’re forcing them in and bending the covers. Think “snug,” not “stuffed.”

Storing upright rather than in flat stacks isn’t just tradition because doing so genuinely protects the spine better and stops the sagging and warping that comes from piling weight on top of the issues underneath. As for how full a box should be, the comics should stand under light, even pressure from their neighbours, enough to stay vertical on their own without support, but with no visible bowing in the covers or bent corners at the edges. If a box feels like a struggle to flick through, it’s too full.

A couple of small habits make a big difference here. Alternate your comics front-to-back as you file them, spreading spine and edge wear evenly rather than concentrating it on one side. And if a box isn’t completely full, use a divider (a stiff, acid-free piece of card cut to size) to break the space up, so the comics have something to lean against instead of drooping. Finally, keep the boxes off the floor and away from exterior walls as the same damp-and-pest logic from earlier applies just as much to where the box sits as to what’s inside it.

Wrapping It All Up: Small Habits, Long-Term Value

None of this requires a science degree or a spare room kitted out like a museum archive. It really comes down to a handful of consistent habits: keep the temperature and humidity stable, keep comics out of direct light, keep an eye out for pests (and remove what attracts them), use decent-quality bags and boards, and pack your boxes sensibly. Do those five things and you’ll have done more for your collection’s longevity than most collectors ever bother to.

Think of it less as a one-off chore and more as ongoing stewardship — the same way you’d look after any other investment. A few pounds spent on the right materials now will save you far more in lost value down the line, not to mention the simple satisfaction of opening a box years from now and finding everything exactly as crisp as the day you filed it away. If you’d like a hand picking out the right bags, boards or boxes for your collection, get in touch with our team and we’ll help you find exactly what you need.

Frequently Asked Questions

1. How often should I check on my stored comic books?

A quick visual check every few months is plenty for most collections. You’re mainly looking for early signs of damp, pest activity, or boxes that have shifted or slumped. Anything stored somewhere less stable, like a garage, deserves a slightly closer look more often.

2. Is it better to store comics upright or flat?

Upright is generally the better choice for long-term storage, as it puts less strain on the spine and avoids the sagging that comes from stacking weight on top of lower issues. Flat storage can work in a pinch, but only if the weight is kept light and evenly distributed.

3. Do I need to use Mylar bags for every comic in my collection?

Not necessarily. Mylar is fantastic for valuable or sentimental books, but it’s genuinely overkill — and expensive — for an entire large collection. A tiered approach, using cheaper polypropylene bags for everyday reading copies and saving Mylar for the issues that matter most, is a perfectly sensible compromise.

4. Can I store my comics in the loft or garage?

It’s best avoided if you can help it. Both spaces tend to swing between extremes of temperature and humidity, and they’re generally more exposed to pests and, in the case of garages, potential flooding. A stable interior room is almost always the safer bet.

5. How do I know if silverfish or other pests have gotten into my collection?

Look for faint yellow staining or tiny pepper-like specks along the edges of pages, along with a slightly notched or grazed appearance to the paper surface. Catching it early and addressing the humidity in the room usually stops it from spreading further.

6. How often should I replace the bags on my comics?

It depends on the material. Standard polypropylene bags are best swapped every couple of years, as they cloud and degrade fairly quickly. Polyethylene can typically go seven to eight years, while good-quality Mylar can last for decades without needing to be replaced at all.