Varsol or degreser of some kind will work for cleaning but make sure
there's nothing left before lubing it. If this was my project,
A-m-s-o-i-l synthetic lube would be my choice.

Clean it off with some diesel or paint thinner. Wipe it down real good
and check the seal and bearing surfaces over before installing it. Look
at the splines and make sure they are not real sharp on the ends and the
same with the bearing and seal step. If you find a real sharp spot dress
it out with a sharpening stone to JUST remove the sharp spots. That
makes it less likely that you slice the seal when you install it. On the
spline end I would put just a light coat of rear gear lube, on the
bearing itself I'd put a light coat of NON moly grease, just plain old
bearing grease. Then put it together.