Originally Posted by slide23
Uh, don't do that. At best, you will contaminate the disc pads as they are porous. At worst... well, think about it.
As I said, I don't know if it works with disc brakes. Works like a charm on rims...
Thinking about automobile brakes, a little oil or grease on the brake pads is not problematic. At worst, you get some burnt oil smell the next time you brake hard.
The idea behind the oil trick is that brake squeal results from slip-stick. Or rather, from a large difference between the stationary (stick) friction, and the sliding (slip) friction. The oil decreases stick friction much more than slip friction, at least between rubber pads and aluminium rims.
It might work with other material pairings as well.