Just when you think you have ask all the dumb questions there are, another one pops up.  I made a reservoir for hypoid oil for the Marcotte Redrive from an empty propane bottle and the inside is rusting like crazy, I seen when I looked into it tonight.  The old mechanic I worked with in the power plant would pour toilet bowl cleaner in something like that, rinse it with water and wash out with Stoddard solvent and that was that.  That didn't seem to effect 35 to 80 barrels of oil.  But I do need to clean that bottle so I can use it.  What can I use safely.  JohnD