Depending on who you ask...
Pop them when they're small and they'll die and won't spread.
Don't pop them ever or they'll spread spores all over.
Only pop them while holding a siphon hose over them.
Never pop them in the tank because they'll spread no matter what you do, pull the rock out and pour boiling water on them.
Don't pour boiling water on them because it kills too much of the live rock. Boiling water doesn't work, use kalk paste.
Kalk paste doesn't work, use lemon juice.
Lemon juice doesn't work, use vinegar.
Get X fish, they eat them.
X fish doesn't eat them, get Y fish.
Y fish doesn't eat them, get Q shrimp.
No, Q shimp doesn't eat them, get R Shrimp.
Ignore them and they'll eventually disappear.
Don't ignore them, they'll just get worse...
Have I missed any?