firstflabn,
I love your researching abilities !

I don't know if you'd call it a cleaning party,
But when called upon to help unpack Small Arms and equipment, My Father said they used Kerosene and or Diesel to remove packing oils and grease (Never heard him say Cosmo), which ever they could get while in the Philippines. Gas was his favorite but was hard to get a hold of. Cut down Oil or Fuel barrels set up for 1st clean, next barrels had cleaner fuel for 2nd clean off. All ended up being fire starter and used oils saved to skim the swamp water to kill mosquito larvae.
He only spoke about putting the bigger stuff like barreled receivers in the cleaning barrels, but also said Serial numbers were kept track of by 'Clip Boarders'. And hanging them to drip dry. Never heard any mention of the smaller parts. Other than there were plenty of guys set up in barracks tents to mess with the small detailed stuff. I do recall him saying they caught H3ll for using the used Diesel or kerosene to start fires to burn off the crates... because of the black smoke and smell.

He had bigger heavy equipment to tend to. So I doubt he spent much time doing the above.