Sorry, these are probably going to be hanging around for a while...There is really no prevention (aside from removing the tonsils).
Thanks for the input.
I tried gargling with Listerine and they didn't budge. I tried spraying them with salt water from a syringe (without the needle) with no luck. So I got a Q-tip and squeezed them out by pressing the side of my tonsils.
Should I expect to have these for the rest of my life or is there a way to prevent them from reoccurring?
Tonsils atrophy as you age, and the pits generally become more prominent. This may be the explanation for why they might start appearing. They are completely benign and are not a cause for concern. Some have bad breath from them and cleaning them out with a water pik or some other device (use at your own peril) may work. They are composed of bacteria and dead skin.