If you don't want to frag and sell the BEST way I found is to inject using a needle syringe with Lugols. Tried Joes Juice, Aiptasia Control, and Kalkwasser. Only thing that really worked was the Kent Lugols Iodine.
Good Luck !
I use a thick kalk paste that I can still push through a syringe without the needle and it melted my green hairy mushrooms. Granted then I will have like three tiny pieces that try to grow, but then I just hit them with it too and bam they are gone.
I agree with the above statements that they're difficult to control but you're best bet for getting rid of them is injecting them with something (into the mouth) like kalk paste, etc . . .