I got a walt melander NEI mold that I have to lightly smoke one side of one cavity for it to perform properly.
I might could lap it a tick or something but all 4 of the cavity's throw boolits so close together in weight and diameter I'm afraid of mucking it up even just a little bit.
that patina [oxidization] Al speaks of is an absolute 100% must have when dealing with a brass mold.
if it doesn't have that bronzing you run the risk of stuck boolits and tinning on the mold face.
Mine is aluminium . Aluminum to those of us in the colonies. Still, Keith mentioned the oxidization issue with steel moulds too, and I've always believed in it. It does makes sense with aluminum too.
In many cases, oxidation on metals that will be subject to heated contact with other metals, helps prevent the adhesion or adherence of the similar or dissimilar metals. In the reverse, this is why acid washing or abrasive cleaning of surfaces must be performed prior to joining via soldering, brazing or welding.
I still smoke it'seems a hard addiction to break.
It depends on what the mold is made of, and if it is used or new on how I clean it.
I like Bon Ami and Barkeeper's Friend. I smoked my first mold that was aluminum, because of the "that's how we do it " Later I just cleaned with hot soapy water. On a couple of old used Iron molds. I have used Wenal metal polish and a Q-tip, toothbrush etc.
I just received my third NOE mold Thursday, I have not been able to do anything with it, but it is an RG-4. I have not ever used a hollow point mold before.
I read some tips on Al's forum about polishing the pins, which I may do as a preventive measure. After it is seasoned and well lubed I hope to just keep pouring lead and making bullets.
I use Boraxo, toothe type brush (Nylon, Harbor Freight) and hot water on all new molds. After they start casting, I don't do anything to them, just put them in a dry place that doesn't change temp very much. I can find no signs of any kind of scratching on my Brass molds with it.