Coral boring spionid worms on hammer. . . should I frag?

[MoshJosh]

Sorry, no picture. . . base of one of my hammers has some spionids on it, they are up to where the coral flesh starts. Usually when I see these guys I try to frag them off and just be done with it, but they are high up enough on the skeleton that fragging above them may cut into the polyp on the inside of the skeleton. . .

thoughts?

I know there is a thread about killing these little dudes with meds. . . and I might do that, but figured I would ask first?

 

[Rick's Reviews]

Various ways to kill them but unfortunately the shell is very strong/ hard to remove, these tiny swirls are like concrete in my experience.
I've tried bleach, hydrogen peroxide baths, fresh water and boiling water on a piece of rock but nothing removed this shell.

From my attempt

Even wire brush on a Dremmel kinda of worked but it took many hours