I hate limit switches!!!

I finally got my limit switches hooked up but not until days of
messing around with the wiring. It turns out that I have so much
noise in my machine wiring that I'm surprised I could hear myself
think. I did a search on this site and others to find a solution, but
it seems that everyone has their own ideas about noise and I'm afraid
I'll die a natural death before I get around to trying all of them.
My setup is as follows. I have 3 non-metallic flex conduits (bad
start). One carries the shielded cable for the 3 motor encoders
lines, the second carries 3 shielded cables for the power to the
servos and the third carries shielded cables for the limit switches.
All cables have a drain wire and a foil shield. The cables that carry
the encoder wires have an additional wire "netting" around them. I
have tried grounding the drain wires from all the cables to the
machine, the computer case and every other configuration I could think
of and, although I get some improvement here and there, nothing seems
to eliminate in completely. The cables for the encoders have 8 wires
in them not including the drain wire. Since I am only using 4 of
those wires. I just folded back the extra wires and taped them off on
both ends to the insulation. Could these wires be picking up noise
and if so, what is a quick fix rather then replacing them?

Thanks
Andre Barclay