Thoroughly rinse out the dispenser bottle until it no longer suds up with the addition of water.
Set the bottle out to dry, with the vent cap removed.
Place sheets of overlapping newspaper on the floor where you plan on transferring the paint so as to protect the surface from any spills.
Using a funnel, pour any extra paint or varnish from partially used cans into the bottle through the vent hole.
Securely twist the vent cap back on to the bottle so it's again airtight.
Using a permanent marker, label the dispenser bottle with the date and paint type; put a small dab of the paint on the container so you can see what color it is.