Before a new coat of paint can be applied on a wall, the old paint must be removed as thoroughly as possible, preferably with a machine. For large areas we recommend the LEROS random orbital sander and for tighter spaces, the smaller DEROS. We recommend testing different coarseness levels on a small area first. The Mirka Abranet and Abranet Ace HD net abrasives have been found to be very durable compared to traditional abrasives, and they resist clogging and deformation extremely well. Adjusting the sanding speed can have an effect on the life of the abrasive. With Abranet discs, we recommend using a pad saver.