All I can say is I am glad we don't find ourselves cleaning parts like some of y'all do.
I am not sure there really is a 'best way' to clean old car parts. Even I am going to be upgrading our system in the future to a baking oven, but presently we use a heated sodium hydroxide soaking tank where the 15% concentrated mixture is heated to around 200° and the parts are submerged for about 12 hours while gently being agitated. After being soaked, they are moved into our Indo jet washer cabinet that has a Zep jet wash chemical in the water that is sprayed at 175° with a 5hp pump. This jet washer uses 12 fluid nozzles placed at different directions covering an 180 degree surface area. The items inside the washer rotate on a large turntable so it sprays from all angles. Generally about 10-15 minutes of cycle time is all it takes to make a basket load come totally clean.
Then we have a large rotary blasting cabinet that has a 49" x 36" drum that uses tiny stainless shot to mediablast (shotblast) parts. The amount of time savings these three machines can give us cuts our cleaning time/costs by about 80%. In other words, what we can accomplish in a day of cleaning & blasting used to take us a week to do the same amount. Even still, it is a nasty job.
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