* Combine cans of paint if you expect to use more than one. If you purchased multiple cans of the same color paint for a large paint job, mix them all together in a five-gallon bucket (or deep-well tray, if you can find a tray large enough for multiple cans of paint) before painting. Pros call this “boxing” the paint. Paint stores don’t always mix paint exactly the same for each can, so if you don’t do this, some sections could end up slightly different in color from others.