It's "medical waste" and your supposed to use a sharps container and dispose of them at a special place/facility. Usually local outreach programs and blood donor clinics will accept them - do some scoping. Your gonna have a hell of a time getting them out of that protein tub - get a BIG sharps container & be safe lol.
the right thing to do is to put them in a plastic bag and toss it out of your car window on the street when there's none looking... always works 4 me