Red's advice is excellent. You should also take care to avoid getting over spray of cleaner polish on your rotors. Unless you cover the rotors when you spay the products, it is near impossible to avoid, so my roiutine is to clean the rotors with a mild acidic detergent as a final step in such procedures. I have success with Windex With Vinegar. If it is glazing on the rotors that is exciting the vibrations, it is also affecting your braking power.