I had about 50 on hold a week ago. I didn't change anything and now there are only 3 on hold.
If they don't move, try keyword phrases more targeted to what you advertise. What goes "on hold" tends to be the more general keywords in my experience. Especially vague, 1 or 2 word combos. They often are words that many novices have bid on and couldn't maintain a decent CTR.
If you haven't already, try different matching options too.
Good Luck!
patient2all