Going to strt using a tumbler and was wondering what is best??? I'm leaning towards corn cob

Birds or mammals? I don't use a tumbler much these days, but I believe certain materials work for better certain critters.

I don't use one much either. If I do, it is for mammals. Just can't get all that crap out of bird feathers, and then they won't lay right.

Hardwood sawdust for mammals, alot of guys will use corn cob gritfor their birds because it is easier to get out of the down feathers. I don't like to tumble my birds, I feel it beats them up too much. What I like to do is after the degreasing bath, place the bird in Acetone ( safer than white gas) which will displace the water and any fine residue of remaining oil, from there I will rub borax into the feathers which will dry the feathers to about 80%, then I follow up with a bird drier to complete the drying process.

SorryFor turkeys