WD-40 is a good penetrant, but you can find even better ones at Pep Boys, Auto Zone, or Checker Auto.
I'd do that first, and if it doesn't work, then holding the well with a pair of pliers, heat the bottom of the well on the outer edge electric stove burner coil, or tip it over and heat the bottom with a bernz-o-matic propane torch or a heat gun on high (red hot is not necessary -- about like a soldering iron's heat is enough.) That will soften the grunge (especially with whatever penetrant is still in there) and then, still holding it upside down with the pliers, give the bottom a good whack with a hammer. That ought to do it.
100% grain alchohol (Everclear) might work but probably not (not strong enough.) Don't worry about getting super glue on the ball, it's very hard and you can pop the glue off with a razor or as I said before, Scotch-brite moistened with a little super glue remover. In fact, scratch that idea! You don't want to inadvertently glue the ball to the bottom of the bearing well!!
If you really don't feel comfortable with any of these suggestions, or none of 'em work, just leave the ball in there. The most important thing is to clean out as much of the old lubricant as possible with solvents, dry the well with a twisted piece of paper towel, and relenish with fresh bearing oil. About 1.0 cc (1/4 tsp) in the bottom of the well or enough to cover the ball, and then coat the shaft before installing. Any high viscosity (40 weight) motor oil should be fine, although I've seen tons of other recommendations here in these forums.
Platter bearing lubricant should be replaced at least once a year (even with minimum use) because it does dry out and get sticky -- but you already know that!
I'd do that first, and if it doesn't work, then holding the well with a pair of pliers, heat the bottom of the well on the outer edge electric stove burner coil, or tip it over and heat the bottom with a bernz-o-matic propane torch or a heat gun on high (red hot is not necessary -- about like a soldering iron's heat is enough.) That will soften the grunge (especially with whatever penetrant is still in there) and then, still holding it upside down with the pliers, give the bottom a good whack with a hammer. That ought to do it.
100% grain alchohol (Everclear) might work but probably not (not strong enough.) Don't worry about getting super glue on the ball, it's very hard and you can pop the glue off with a razor or as I said before, Scotch-brite moistened with a little super glue remover. In fact, scratch that idea! You don't want to inadvertently glue the ball to the bottom of the bearing well!!
If you really don't feel comfortable with any of these suggestions, or none of 'em work, just leave the ball in there. The most important thing is to clean out as much of the old lubricant as possible with solvents, dry the well with a twisted piece of paper towel, and relenish with fresh bearing oil. About 1.0 cc (1/4 tsp) in the bottom of the well or enough to cover the ball, and then coat the shaft before installing. Any high viscosity (40 weight) motor oil should be fine, although I've seen tons of other recommendations here in these forums.
Platter bearing lubricant should be replaced at least once a year (even with minimum use) because it does dry out and get sticky -- but you already know that!