This one is a little out of order, as I do this slot by slot when fitting frets. You can do this straight after cleaning the slots or like me, before inserting frets. Using a triangular file, carefully bevel the fret slot. This helps both for the fretting - by easing the slot edges to accommodate the tiny fillet between the tang and underside of the crown - and also for future maintenance work, by helping to prevent excessive chipping should frets need removing. It doesn't have to be large or pretty, it's purely functional. Again, blow out any junk.
Also, call this adequate time to mention (again) how difficult Maple is to inlay.