I've never heard of the marbles idea, but it sounds like a good idea! POR recommends placing plastic film (saran wrap) over the top of the can before resealing. What I've always done is layed the saran wrap over the can and pushed it into the can to just touch the top of the paint but make sure it still overhangs the sides of the can. Then seal the lid tight over the saran wrap. This displaces the air to above the saran wrap (very little on the paint side), and keeps the POR from literally welding the lid shut.
The idea is to keep the air off the POR by any means possible. Also never paint from the can, I always pour it into a paper cup to work from and reseal the can immediately.
The idea is to keep the air off the POR by any means possible. Also never paint from the can, I always pour it into a paper cup to work from and reseal the can immediately.
