I once heard a song lyric that went “I’m gonna let my yearning shine”. I thought it seemed like a good idea, so I tried it. The end result of that is a mental layer/object that burns itself and others, is spikey, and has little to no energy to correct itself. You probably have areas like this within you now, but they hide their destructiveness behind unchecked desire. Even the desire for all beings to be blamelessly happy can be corrupted in this fashion.
Let’s say you’ve found one of these and can see that it is hurting you, others, or both. You realize that it is an unskillful action with painful results, painful consequences, so you want to desist. Let’s further say that MN 20 has failed. I recommend the following plan of action, first, relax away the problem thought, by seeing that it hurts you, seeing that that way of thinking hurts others, seeing that it hurts both you and others, seeing that it blocks wisdom, and does not lead to nibbana. then regard, look at, and inspect the memory of the allowing of the yearning to shine in such a way as to impress upon yourself that such yearning shining is blameworthy, this is done best with this tool. When that is done, replace all thinking in the area with goodwill, then mark yearning shining as blameworthy by regarding the mistake as a mistake for the sake of self improvement.
When you have enough practice, you will be able to prevent the re-arising of this unwholesome state by remembering how you got rid of it, realizing that the plan worked, and feeling rapture and pleasure at having done such a good deed as removing that unwholesome state.