I'm cheap
when I need to change colors I just add the new one to the bowl. Eventually I use up all the old color
I've been working on getting rid of some light green. Never liked it and figured once it's gone I can 'enjoy' my reds and blacks, etc.
I put some of it (actually a great deal) into a bowl that had Smoke's copper in it. Not very much copper as the resulting powder looked as green as that in the jar.
bullets were coated in green powder before the baking--again same color as in jar
when I baked them = they were brown with just a hint of green. Amazing how the copper overrode the green.
at the end of the day it doesn't matter as they all do fine coming out of the barrel
just an observation during our forced quarantine.