When I first began buying used books by mail, about half arrived with the dustjacket in its original state, while the other half were encased in plastic dustjacket protectors. Sitting side-by-side on my shelves, I couldn't help but notice how much nicer the latter books looked. The mylar protectors gave these volumes a bright, fresh, downright spiffy (first AND LAST time that word will be used on this blog!) appearance. They reminded me of library books -- and who doesn't love the way library books look? Those without the mylar covers looked sad and almost naked in comparison. Their cover art and titles didn't "pop" (another twee word I think I'll avoid in the future) but seemed dull, dreary, and lifeless. Over time I also noted the utilitarian benefits of mylar as my "naked" jackets began to suffer the effects of rubbing, tearing, and chipping at the spine ends; those with dustjacket protectors didn't have similar blemishes, tears, or chips off the old book.
I then decided I wanted all my dustjackets protected, but had no idea where to purchase these types of covers. I asked around at antiquarian bookstores and discovered that some sold these covers individually -- with prices running anywhere from thirty cents for a Beatrix-Potter-sized volume to maybe a dollar-fifty for a Van-Allburg-sized behemoth. Later I learned you could even order them in large quantities directly from library supply companies such as Brodart and Demco. Today all you need to do is visit eBay and type in "Brodart, covers" and you'll find a wide variety of shapes, sizes, and prices.
Every serious collector I know covers his or her dustjackets in these protectors, though I'm sure each one has personal preferences when it comes to brand, style (some protectors come on a roll; others as separate pieces), size, weight and glossiness. Some may prefer to fold the protector into place, while others tape it for a snugger fit. (I'm sure ALL agree that one NEVER EVER tapes it onto the book!)
Although I love my mylar covers, I will say that, once I cover a book, I sometimes miss the tactile experience of touching the original dustjacket -- especially those rough, papery, matte-like jackets still occasionally produced. (Recent examples included THE WILLOUGHBYS by Lois Lowry and THE AURORA COUNTY ALL-STARS by Deborah Wiles; actually, all of Wiles' novels have featured beautifully-illustrated matte covers.) It should also be noted that covering a book in mylar does not prevent the original dustjacket from sun damage. (And can some scientific-type explain to me why the sun can BLEACH some dustjackets to the point where you can't even read the title on the spine, yet in other cases it DARKENS the dustjacket to similar detrimental effect? ...And while we're at it, why does the sun lighten some people's hair in the summer and darken others?)
At least one book dealer I know deacidifies their dustjackets, describing this as a chemical treatment which "does not restore paper to its original condition, but stops any further browning, brittleness, and acid deterioration." I think I'm going to look into this next to learn whether we can all do this at home, or whether it's a process best left to professionals. I definitely do not want to submerge my valuable WRINKLE IN TIME dustjacket in some type of chemical solution and see it disintegrate into a million pieces!