1.) When you first open a new can of paint clean the paint off of the underside of the lid with the brush you will be using and scrape it into the can. This helps keep your lid and rim clean for re-sealing.

2.) Each to you pour paint into your roller pan use you brush again to keep the rim and outside of the can clean.

3.) While painting and again when you have finished clean the rim with your brush and scrape the paint from the brush back into the can again.

4.) Place the lid on the can and cover with a rag. Seal with the rubber mallet. Remove the rag and visually check the seal. If you do not have a rubber mallet, put the rag on top of the can, hold onto someone's shoulder and walk around the rim of the can.