How do you stop exploiters effectively as possible?

I've recently been getting some exploiters in my game. Essentially, the exploits would start making parts change color, and it would turn my entire game into a rainbow.

I have Filtering Enabled turned on, and I checked all scripts for "getfenv" to remove backdoors. I found a bunch of them, deleted all of them, saved and republished the game, however, it still keeps coloring my entire game.

Is there a way to stop this from continuing on? I'm not sure if there's still some other backdoors in my game, but it's getting kind of annoying to continually shut down my servers, even though it is a harmless color exploit. Thank you!