Does anyone know how to remove those stickers that leave behind that gummy residue?

There is a product called GooGone just for that purpose. it smells like oranges and it's a bit greasy, but you can wipe the grease off with another cleaner.

Eucalyptus oil. You can buy it in little bottles from the chemist and some supermarkets. It is guaranteed to get those difficult stickers off anything. I used it on a wooden door of a house I bought and the previous tenant had kids that were 'sticker happy'. Got it all off and it leaves a lovely smell too!

You can buy a product called "mess master" from most craft stores or walmart..it will take the sticky goo off easily...

Nail polish remover

Depending on the material you can use goo b gone. Good Luck

I use Citra Solv to removes stickies. Its my "go to" product.

I've always used liquid lighter fluid, does the job well

cheap white spirits, or the stuff that clean your plastic window frames

Use goo-gone or a heat gun.