Actually, Koda May, I did that a while ago and all it did was give me portals to the deleted maps and when you go inside the game crashes... Weird.
I'd say, to prevent the problem I had and risking losing your characters when they accidentally go inside the broken portals, just delete you Feralheart folder and save any maps you DO want, then reinstall the game and folders entirely. Worked for me, and actually gets rid of some of the lag in fluorite.
