What is the best way to remove children's stickers from a mirror ?

Pull off as much of the sticker as possible,then apply oil,d40,rubbing alcohol,or white vinegar too remove the residue.

Peel off as much as you can. A putty knife, butter knife, or razor blade (carefully) will work. Use Goo Gone or WD40 to remove what remains and the adhesive.

I've had success with WD40, it works miracles!!

I would use alcohol

WD-40 or spray on glass cleaner should do the trick. And patience.

thank you all for the suggestions, the vinegar took them off

Coconut oil!

use your hair dryer or hot air gun. it softens the glue on the back and it peals right off. No scrubbing!

Eucalyptus oil will remove anything sticky and gooey

Start with trying to peel the sticker off, work gently so you do not scratch the mirror, use a plastic store card as a scraper, but gently. Now you may have glue residue left behind by the sticker. For that either plain water or soapy water can be used. With a moistened cloth, wet the the sticky part and let it set for a few minutes, see if it will peel off. If successful, keep going. If not then try olive oil, to do this take a clean dry rag and put some olive oil on it, apply it to the sticker and work in small circles, the adhesive should form little balls and fall off. Remember to not press too hard.