teflon tape (for piping and whatnot) works wonders for de-slopping ball cups. it's usually unsightly, but a small piece of tape folded over itself to make a 1/2" x 1/2" square shape draped over the ball before the cup is pressed on is an awesome solution. at first it may be slighly too tigh, but it will mold itself to fit the larger cavites in a few runs, and does not restrict movement like orings do.