You didn't specify where the pits were but I use a single cut machinists file and a technique called draw filing. It is easy to learn and really removes the pits.. Done right it leaves a smooth finish nearly ready for a 'hunter' grade cold blue. If your looking for a simpler technique then simply use backed sandpaper.. Start at about 100 grit and progress theu 220. Finer would not be necessary for a hunter grade finish. I would use OxphoBlue liquid from Brownells.. It produces a very durable finish with only the cost of the bluing agent itself.. I prefer the liquid as it seems to produce a more even finish. Moer than a single coat is usually needed and with OxphoBlue cleanliness is much less important. A bit of oil won't harm the result. Don't work straight from the bottle, I put mine in a squeeze bottle and apply as needed. For applicators I prefer the cottom fiber pads women use to apply/rmove makeup held in a cheap Chinese forecepts. Wet the applicator and rub the surface and keep it wet.. When it doesn't seem to be getting darker dry and do another area. Drying the surface will help keep down any tendancy to blotch. Heating the steel is a good idea as it speeds up the reaction. Don't get it so hot as to sizzle the bluing, just warm to very warm.. After a coat is applied and the surface dried off burnish with medium to fine steel wool (00,000). This will bring out the best color. To darken just apply another coat.. After a couple of days curing time the surface is very wear resistant.. Good luck. Brownells has an ecommerce sight,.,.