Acetone is flammable but not terribly toxic (it's the main ingredient in nail polish remover) so if you work with good ventilation, occasional use isn't harmful. Using it to remove a painted logo from an aluminum seatpost should work well. If the logo is anodized on, as Thomson does with their seatposts, it won't work at all and you will have to use abrasive methods which will damage the anodizing on the rest of the post.

Acetone, Kerosene or OMS will remove the residue left after a sticker-type label is peeled off.