We recommend cleaning the affected area with mineral oil followed immediately by rubbing alcohol. The action medical community refers to this procedure by the acronym "MOFIBA"
It is important to work only on small, manageable areas of the body. If the mineral oil remains on the victim's skin for too long (30 seconds or so) the pain can worsen and burns can begin to form. Do not begin the procedure unless you are sure you have enought time to finish (ie, the scene is safe).
Wet a 4x4 pad (non-sterile) or similar material with mineral oil. Carefully avoiding the eyes, thoroughly rub a small area of exposed skin with mineral oil. (You can use any vegetable oil in a pinch).
Quickly wet another 4x4 pad with rubbing alcohol, and vigorously rub off the mineral oil. Be extremely careful around the eyes. Fold the gauze as you use it, so that you are always using a non-contaminated part of the gauze.
Again, be careful to fully complete this procedure with each victim - mineral oil left on the skin may act to bind any additional pepper spray and cause the victim unnecessary pain.