Once they are abundant in your tank, they're incredibly difficult to eradicate.
Food portion control helps, manual removal helps, superglue over the tips of the ones you can't remove.
Get a new wrasse (halichoeres genus, or 6-line) every few months until you find one that will eat them (I know I have one/some that do, because I stopped finding them in my tank).
Allegedly bumblebee snails will eat them, though I have yet to see it in action.
Overall they don't do much harm. You might see reduced polyp extension on your SPS, and slightly slower growth. But they won't kill your reef by any means, so not something to stress about.