Are you talking about using "fuel magnet" on the spark plug wire?
I searched for "clip on RF Filter" and got these, which look exactly like the "MIT designed magnetic fuel activators" I got from a catalog for $10 each
I don't know if they increase fuel mileage, but I suspect they would stop any metal flakes before they reached the filter or engine.
I used to have no problems with my cyclo computer, but lately its reset every ride. I tried a new battery but it still happens, so I am thinking that the new wire routing (the traditional spiral around the handlebar and brake cable to the sensor) is exposing it to more to the spark wire radio interference.
I'm going to try unspiralling it and wrapping the wire in electrical tape.
Then if I have to, I 'll try putting a "fuel magnet" on the spark plug wire.