I have a 99 150 4x4 with disc brakes all around. Lately the brakes have been squealing alot, almost everytime I press on the pedal. I took off the tires and looked at the pads, there was still plenty left and the rotors were hardly worn. I haven't been in any mud lately. Could it just be brake dust? Do any of the wheel and brake cleaners I have seen adverstised really work?

I'm going to make a guess, that the pads are not factory, and the rotors are likely not either.

There are lots of causes of squealing disc brakes: Glazed friction surfaces, hard rotors, anti-rattle clips broken/missing/ineffective, no "anti-squeal" compound applied at last brake job to the BACK of the pads, sticking caliper slides OR piston(s), loose wheel bearing(s). The list goes on. The best way to prevent excessive brake noise is to use GOOD pads (OE, Raybestos), replace the rotors with GOOD ones (OE, Raybestos, Brembo), and carefully inspect the calipers, anti-rattle clips, and other hardware for wear and free movement.

Unfortunately, rinsing off the brakes is usually a very temporary fix.