rear abs sensor ring

[Ryoken]

Well, ive had 3 yellow lights on for a bit now and I'm getting hacked of with it .
decided to sort it out
been over to garage to get my codes read , rear right sensor wasn't working , . that was a wiring fault , that got rectified on site.
left garage , and went down street.
when you brake the pedal judders , like you got a sticking calliper . ( thought , great this again, I know what's going to happen next). next thing PING dsc inactive
returned to garage ,again , rear sensor.
he said you might have some crap on the sensor ring , clean it off and try again,
so I went home , removed wheel and took a load of mucky grease n crud
now I know I've not got all of it off
now what's puzzling me is this, the rear bearing is only a few months old , and I cleaned the outer surface when I installed it , so where's all this grease n crap appeared from.
next question , is ive used wd40 to get it all off, but its being stubborn, what do you think I should use?
plus, can you get to the sensor ring another way to clean it , or is it just through that little hole? ( sensor)

I'm getting rather annoyed at this now