I am currently annealing a forend iron that I will then fit to the frame of a Parker. The key is to thoroughly clean the steel of all grease and oil with solvents and scrubbing. Then, using a lidded crucible, put the work inside and bury it completely in pure wood charcoal granules like those sold by Brownell's. Put the crucible in your kiln or furnace and heat to 1450 F. Hold it at that temp for an hour and then turn the oven off and walk away. Let it cool down over night before opening the kiln or crucible. It is very important that the atmosphere does not touch the work until it has cooled to room temps, or it can be ruined by the instant formation of hard gray scale all over the surface. But so long as its buried in the wood charcoal in the hot lidded crucible, it will be enveloped by a cloud of carbon gases that will prevent hard scale formation. When you remove it from the charcoal pack the next day, it will be fully annealed. After engraving, it will need to be bone charcoal case hardened again, which is best left to a pro if you want to achieve accurate case colors on the finished product.
