You really can't, unless you could lay the motor on its side and allow it time to ooze out. I have a vacuum pump with a hose, but was only able to retrieve about 1/2 cup of it. Plenty remained. It's thick and doesn't suck out well at all, even when warm (it actually never gets warm there).
I have a theory that it is a buildup of condensation.
Doesn't matter I guess, since those motors aren't likely to live past 8-12 years anyway. π