A follow-up question – if there is wet paint or varnish or etc in the can rim how do folks clean it out before putting the lid back on? When I try to run a rag or swab around the rim I just chase it in circles, and half of it drips down the outside of the can.
It's probably a no-no but pretty much any can I open gets a ring of holes either drilled or poked with the corner of a straight screwdriver so that the spillage in the lip drains back into the can.
Alan