If I didn't mix the color and just used it straight, I will often pour it back in the bottle. If it was a mixed color, I pour it into a little cup until I have finished the pattern in case I need it again. When the pattern is done, it goes into the slop jar. I try to flush the gun between colors. I use urethanes, so I run a little lacquer thinner through. If you use Createx or similar, they make an airbrush cleaner. You can run just water through but use the cleaner every few colors to be sure. Also check the tip for paint accumulation because this will cause the spray pattern to degrade as you are working along. A quick wipe with with the appropriate solvent on a qtip every couple colors keeps that line fine. Hope this helps.