I've been using these Max Flex disc's to clean up aluminum castings. They have 24 and 36 grit depressed center disc's for angle grinders. There is another called Aluminator but I haven't tried it. https://www.rexcut.com/products
I occasionally use flap discs and cutoff wheels designed for aluminum, but most of my parts are used as-is or destined for the lathe/mill so I don't use them often. I haven't tried a lot of brands, but Benchmark Abrasives have thus far been the best I have found.
We usually use tiger disc....flap disc. I also have found that using Johnson's stick wax makes grinding aluminum so much easier with whatever you use!
I found their aluminum cut off disc's on Amazon. Ordered a pack of 25. Sometimes I get a little uptight de-sprueing an odd shaped one on my table saw, maybe this will relieve some of the angst. Thanks
I've used Pam, WD40 and wax on the table saw blade and the belt sander. My problem with using them is a lot of my castings get powder coated and it causes more work cleaning them. I can use it to de-sprue though. Thanks Billy