Does anyone have any tricks to removing a sticker and reapplying, after a significant period of time? I recently purchased a lot of sets from 2000-2010 range, and the stickers look like they were applied by my 4-year old, while blindfolded... I'm dealing with sets like Town Plan, and Joker's Ice Cream Surprise, so purchasing new stickers is not an option, and unfortunately stickers really make the sets in these two instances. I'm hoping someone has experience with using a glue or something else to repair the adhesion. Thanks!
Unfortunately older stickers are difficult to remove and reapply because the sticky part of the paper tend to rip off and leave a residue on the LEGO element itself. But the fact of the matter is that applying that taking off and re-applying even a new sticker is a challenge and it will almost always be visibly damaged at least a little bit.
Your best bet is just to get new stickers. You can find pretty much any sticker-sheet LEGO ever released all the way back from the beginning, and many times in new condition. In fact several Bricklink stores specialize in selling old stickers.
Just go to Bricklink, type in the set number and look at the inventory listing. The sticker sheet will be included there. Then see which seller have it at what prices and choose the one you like the most.
Here is the general listing of all LEGO stickers: http://www.bricklink.com/catalogList.asp?catType=P&catString=160
To remove stickers, I use lighter fluid. However, it can damage plastics, and I've never used it on LEGO bricks before, so please test it first.
Apply the lighter fluid to the sticker, and use a sharp metal object (like an X-Acto Knife) to slowly pry the sticker from the brick. You will probably have to regularly apply the lighter fluid as new parts of the sticker are exposed.
Once removed, set the sticker grahpics-side down a piece of newspaper or other disposable surface. To restore the stickiness, spray the back side with spray glue or spray adhesive, available in most craft stores. Now, immediately reapply to your bricks.
CAUTION: chemicals like lighter fluid, Goo Gone, spray adhesive, etc. can damage both the stickers and the plastic bricks. Test this process with an unimportant brick first.