how do you do it

are you refering to decales under a clear coat, or over a clear coat?

the ones not on the tank...that is not under a clear coat....there's a couple of ways but the BEST way...the way i removed mine is a two step process....

1) get a blow dryer or heat gun and heat up the sticker...will allow it to pull off...do it slow or it will tear....all it's going to do is remove the actual sticker...you'll have an adhesive residue where the sticker was...which leads to step two...

2) goo-be-gone...get a ton....put it on...try not to let it run..let it sit....then rub and rub and rub..with a non-scratch rag from a detailer or auto parts store....keep putting on the goo until it all comes off....

3)...move onto the next... ;)

Some auto detailing waxes and polishes takes off the adhesive just fine.

WD-40 will take off the goo too, or denatured alochol, and its gentle on the paint