Okay, so first of all... you are going to get 9000 different suggestions here, from sound advice to absurd. Prepare yourself.
Second, CBBFs don't eat majanos. They will eat aiptasias. There are butterflies that will eat majanos, and a few angels. Top of my mind would be raccoon butterfly and the bicolor pygmy angel. Both have issues, both will eat other things in your tank. Frankly, I don't proscribe to animals for majano control.
Now for the method I find best. The big difference between aiptasias and majanos as far as removal goes, is that majanos do not retract into holes in the rock. They mostly attach to surface rock, and you will be able to get under tham with a razor. So: take a clean razorblade, and work it under the base of the majano. I do this out of the tank when I can, but works either way. Scrape under him, he will pop off and float/sink. Suck him up in a baster and in the garbage. Repeat.
You may think this won't work, but it does. Unless you have a million of them already, you can battle and beat majanos. They grow slower and don't fragment as easily as aiptasia.
Good luck.
S !