More recently applied stickers should come off easily with a bit of gentle heat from a hair dryer, but sometimes the paper on old ones seems welded to the wood and brittle from age.
To get this mess off, the trick is to lightly "scuff" up or gently score the surface with a flexible piece of plastic (a credit card is perfect) then apply either a commercial product such as Goo Gone, or if you're a cheep bastid like moi, good old vegetable oil from the kitchen!
Let it soak in for a bit, then start pushing the gummy residue off with the card. Depending on the condition it may take several applications, and the vegetable oil will definitely take longer to work (but it's already in your cupboard).
The key is patience, keep at it and it will come off.
"A little song. A little dance. A little seltzer down your pants." -Chuckles the Clown
GUITARS : https://legend.barryeames.com/guitars.html
MUSIC/PIX/VIDEOS: https://getback.barryeames.com (including Spectrum ST)