Decals!
I hate the word, I hate the product. I have Good Luck with them, I would just rather use "Letra-Set or something like that. Now here's a real conundrum. I got four free Vessels at the model show and contest.All four were very old Revell Ship models.
The decals started falling off the "Randall" and I saved them to Decal backing paper after I slightly moistened them. Now they are all doing it! The funny part? On all of those ships I have New Decal sheets in Zip-Loc bags in the kits. Some even have two or three full sheets, I was given in a paper bag at one model show!
So even though I have a Love-Hate relationship with Decals I use them. The last time I tried to remove some was when I was doing a restoration of the "Hawaiian Pilot-C-3 Freighter" from Revell! Those were so stuck and brittle even after soaking with Solva -Set they had to be scraped off!
So-In closing, when you get an old model with decals look at them carefully, You might be able to Save Them? Promise not to laugh? I have removed some intact from a model by soaking them in "Pickle Juice" Yes, "Pickle Juice" from a jar of DILL pickles. Do not use the juice from Sweet Pickles!