Roller

When a roller is used for epoxy, don't even think about cleaning it. Just try to keep the epoxy out of the bearings. If epoxy does get in the bearing area and the roller doesn't... donate it to the trash.

When a roller is used for paint or varnish, cleaning the roller is possible.

Before the coating dries on the roller, use the edge of a paint stirrer as a tool to strip the paint off the roller. Use the stirrer like a knife, peeling a potatoe with a fair amount of pressure. Work around the roller 3 or times until it seems like no more paint/varnish is going to come out. Then paint some newspaper with the roller or use an old rag to remove even more paint. When this is about done, begin using water (for latex/water soluble) or thinner (oil based varnishes etc.) Just use a little solvent and then strip the roller again. Repeat the process 3 or 4 times, until the roller is clean. For Latex paints, keep stripping the roller under running water for several minutes, then add some degergent and work it in with your hands. Then begin stripping the roller under running water again.

You may finish the cleaning by rapidly rolling the roller on grass to use centrifugal (actually centripital) force to get the water out of the roller. (For oil based paints, after the thinner is clear during the cleaning, wash the thinner out with water and detergent. Rinse well then rapidly roll the roller to get rid of water.