I can't really work out how to cripple them in the editor as big clubs always seem to make money in a hurry.
To cripple them with the Mind Compression thing, set the wages to about 100000, the finances to -25m, then everytime they "make arrangements with their creditors", chop it down to -25m again. Only takes a couple of months to bankrupt them and with the low wage they can't sign anyone anyway.
If you want to ensure they don't recover easily from their bankruptcy or don't mind them having long-term issues (if only using editor), reduce the stadium capacity to 1000ish, and the maximum attendance to about 50. Without gate reciepts it's very hard to make money
I like the randomness that comes from ensuring Man U, Arse, Chels and Liverpool aren't factors in the game, so good luck with it.
VB