I have two “go-to” breakfasts I make for myself. One of them is oatmeal, which I like to dress up with raisins or currants and a bit of brown sugar. I also like to add about a teaspoon each of ground flaxseed, chia seed, and hemp seed. I use a coffee grinder to grind the seeds, but their oil content causes them to form a packed mass that is hard to get out of the grinder.
However, if you put a teaspoon of uncooked oatmeal into the grinder with the seeds, it absorbs enough of the oil to keep the result “loose.” Getting the ground seeds out of the grinder is quite easy and cleanup becomes very simple.