General usage notes: (i) always select the least aggressive disc you think you will need to achieve the desired result, and step up one grade at a time if more cut is required (ii) always ensure that you centre each disc properly on the backing plate (this can take several attempts to get right, but is vital if the machine is to remain perfectly balanced during use); (iii) always use an appropriate sized disc for the backing plate you are using (the disc should always protrude past the edge of the backing plate, never the other way around); (iv) always prime a new disc by spreading a thin layer of product over it and running it stationary on the glass for 15 seconds at low speed; (v) always ensure that spent polish residue on the face of the disc is cleaned off regularly during use using either a compressed air gun or a PB Utility Brush (failure to follow this advice can lead to a significant reduction in cutting ability, so don't be lazy!); (vi) after use, soak each disc in a bucket of PB Snappy Clean Boost solution for 15 minutes and then rinse under fresh running water (using your fingertips to massage out any remaining polish residue) and allow to dry naturally, and; (vii) while not in use, store in a dry, dust-free environment (lidded plastic storage boxes are ideal in this respect).