I've seen people around here say if one's having grip problems he should do some barbell holds at the end of his workouts...
How about -=towel holds=-?

I just tried and it's brutal, I can't hold myself for more than about 12 seconds :/
Wouldn't those be better than barbell holds because here you use your thumb as well?
Anyway I never did see anyone write how exactly is one supposed to do this... 3 sets of the max time you can hold on? Will doing this every other day be ok?