Just pull it off if it lets you. If it wants to stick,you can try to heat it up just a bit with a heat gun and it might help to loosen it. Usually if it does leave some residue behind,you can light heat it and rub it off with your fingers. There will be some tid bits and stuff that you just wont be able to get off and you'll have to use a razor to get under it and peel it and stuff. It doesnt hurt to rip and tear all you want,but its best to go slow and try and take off larger chunks(use heat gun if needed) as too many little slivers makes for headaches. I have noticed its hard to sand it off,so be careful when doing so as you might get high and low spots in the balsa. Have fun.....I'm sure it will look alot better afterwards then it does now. I've recovered a few planes now,and they turned out great!