This in Facebook. Seems to make sense to me.
"Storing Plastisol over time: As bait makers, you may already know this. But it is something I learned today and wanted to share if you didn't think of it. An old friend told me today about the settling of plastisol when stored, about stirring over and over again before using. This is what he said to do; Cook all of your clear plastisol and pour into a tray to harden. Then cut it into cubes of 1oz size (like an icecube size) and store them. When you need some, take out as many cubes, cook and add color as needed. Anyone do this?"