Yea, it should not be a problem in the first place. Don't keep your hands still - movement hides irregularities. Watch your angles. Use clean wax if the old stuff starts to get dark.
If a spectator notices, ditch it. In the action of moving your hand up to eye level to see what the spectator is talking about, ditch and drop it. When you turn your hand for your spectator to see, you can quickly take care of any residue. Always be ready with a follow up trick, as you may not be able to perform the trick you were planning on if you have to ditch.
// L