Deparafinize FFPE tissue section is carried out as outlined in your protocol. Hydrate tissue with PBS. Remove buffer, add 2-4 drops of Pepsin reagent to cover tissue section. Incubate at 37oC or at 56oC for 5-10 minutes (the time required for optimum digestion of FFPE tissue section will vary with the extent of fixation, generally approx. 5-10 minutes are sufficient at the above temperatures. In some cases it may require 15 minute.). Discard Pepsin reagent, wash 3-5 times with buffer.