In the past when I was an apprentice besides making the Tea by gallon one of the other chores was to make penetrating oil that was used by Engineers all over the works. Now I am not saying it was the best or any such other recommendations only that it worked well and is extremely cheap to make up, it was so cheap that there where buckets of the stuff doted over the factory each with a lid. If there were a lot of sized parts and the object was small enough it was put in one of the buckets and left there for as long as it takes.
Now I still make this up for use in my own workshop and it uses only three ingredients which are � pint of Paraffin Oil (Kerosene) � pint of cellulose paint thinners (the cheap stuff, the type for cleaning spray guns) and the last ingredient is a large spoon full (about 2 ounces) of Molybdenum Auto grease stirred in. The cellulose thinners do evaporate quickly so you do need to re-apply it. But if you can put the part in and leave it soaking you do get good quick results.
