Tell me if I'm wrong, but I don't think you should be able to use cleanse on a square marked with a mine.
152 days ago (+1)
How to Break (Some) 50/50s
Chapter 1 - Cleanse
When you left click on a number, if the correct amount of mines surround it, all the unknown tiles adjacent to it will be opened. This is called Cleanse.
Chapter 2 - Cleanse?
If you left click on a flagged tile, and a number is under it, Cleanse still works. This glitch is the key to breaking some 50/50s.
Chapter 3 - Cleansed
Consider the above scenario, where the "4" on top has one more mine near it and the top "2" also has one more mine near it.
Without this method, you would have to guess, which can be frustrating if you lose a good board over luck.
However, by attempting to cleanse a tile with flags where mines would be if it's a number, either:
The tile is a number, in which the cleanse will succeed, you know it's a number, and the 50/50 is broken.
OR
The tile is a mine, in which the cleanse will fail, you know it's a mine, and the 50/50 is broken.
Chapter 3.5 - Uncleansable
Unfortunately, this doesn't work for all 50/50s, like the above scenario.
If (successfully) cleansing had a sound, any 50/50 could be solved, because you would be able to determine if it can cleanse, meaning it's a number.
Closing Remarks
While this doesn't completely remove 50/50s and it's based on a bug, it can remove a decent amount of luck from your games.
Thanks for reading this, Please give me a like, and have fun!