Fixing linedefs that cross

[Jellybones]

When all is said and done, is there a way to fix these? I can't really delete them as they're attached to a whole bunch of other sectors (I noticed it too late, unfortunately), but they create slime trails and connecting anything else next to it makes even uglier bugs appear. SRB2DB provides some sort of explanation to fix it but I don't understand it.

Is there a way to fix this? Help would be very much appreciated.

 

[MascaraSnake]

Try to insert a vertex at their crossing point? You might have to correct a lot of wrong sector references afterwards, but that's pretty much unavoidable.