I was in your spot twice. Basicly you can't. When those go you can
have them replaced or replace the whole drive shaft. It's almost
better to do the drive shaft with the boots factory sealed then have
them manually replaced. Opinion here, i went for the whole drive
shafts. for my '92 accord, aftermarket thru honda was only like $150
a side w/a 1yr warranty. You can pack grease if you want but as it
spins all it will do is loose this grease and you'll see what's
covered by it. Maybe you can buy some time this way don't know, but
for the long run, you have to get new boots one way or the other.

jdc