So what do all of you do to make the stickers on your sets stick to the bricks permanently, or at least make them last longer?
I once tried a clearcoat (I cannot remember which one) but all it did was make the stickers look oily. Because these stickers were on a very curved surface, their sides lifted up and the clearcoat did not seem to help.
I have read that several people cut clear tape in the shape of the sticker and apply it over the sticker, and though I have never tried this method it does not seem to be effective to me. Essentially you are putting another sticker, with a tendency to peel up over time, over another sticker. Also, because I own hundreds of sets, each with tens of stickers, cutting tape in the right size for every one of them is too big of a task.
I have also read that some people use nail polish for stickered models or other toys, though I do not know if this works well for LEGO stickers. There is also the fact that acetone and ABS plastic are not the most friendly combination, though in the right concentration apparently acetone kind of binds the sticker and its colors and patterns to the ABS plastic.
Also, before you add some kind of coating on these stickers, what kind of glue or adhesive would you use to flatten curled-up stickers?
Please leave your thoughts and ideas or proven methods in this topic, I am very curious.