If you don't care about the seal and you plan to throw it away I have several solutions that works for me.
First you need to identify the type of paper the box is made of, there are three tuck paper qualities:
1. Generic glossy finish (This would be the same type used on common bicycle decks, has a smooth business card feel to it).
2. Coated (This would be the same type used on the red monarchs and medallions, has a waxy smooth feel to it).
3. High quality paper (This would be the same type used on copper rarebits, mystery box, and most other t11 decks, has a printer paper feel to it.)
If you are dealing with a glossy finish tuck case you can cleanly remove the seal by either starting from the corner of the seal and peeling it off (I usually start on a corner on the back of the box, never the top as it goes against the cut of the paper). Another way to do it would be to cut the sticker down the middle in a way that blocks the thumb cut (so basically in a straight line). This allows you two peel the sticker off in two parts. First you can deal with the part on the back of the box. To do that use the method in part one to remove the first half, then you can deal with the part on the flap. To remove the piece on the flap you can start at the edge of the cut (because you cut it there should be a little bit hanging off the edge to get a grip on) and peel off.
If you are dealing with a coated tuck case you can very easily remove the seal. To remove start at one of the corners on the back of the box and work the sticker in a fashion so the whole bottom of the seal is lifted up, than grab the middle of the bottom and peel up to work with the thumb cut on the box. Coated boxes are easy to remove seals from as the adhesive doesn't stick as well to the wax coating.
If you are dealing with a high quality paper tuck case you have to peel slowly. Start at one of the bottom corners and work the seal so that the bottom is raised (like the coated tuck case removal). Peel very slowly upwards as to not damage the paper. Once you clear the back portion of the box you should adjust your grip so your peeling finger is as close as you can get it to the paper on the flap. Peel slowly and carefully until the sticker is off.
Cleanup
Once the seal is removed there will be residue from the adhesive on the sticker, to clean it up I grab a small piece of tape (I use Scotch Satin finish or Matte finish as those are the weakest clear tape types I know of), try to avoid using packaging tape as that will have a higher chance of damaging the box or the ink/foil on it. Hold it with your index finger and use your thumb and middle finger to maintain a grip on the tape. Lightly dab the areas with residue repeatedly until it comes off, check the tape every couple of dabs and get a new piece once the piece is covered with adhesive.
-Bryant