Did you know there are 101 uses for duct tape?
A tip for paint sample removal by Phil Beckwith of Topp & Co
Put duct tape over the area from which you want a sample, then tap with the round head of a ball peen hammer. Remove duct tape complete with sample of paint. If you want a neater sample, do as above, but before tapping use a Stanley knife to cut a square shape making sure to cut right down to the metal then just tap this square area before removing.