That's really wild, I don't know how I'd react if I saw that for my owns eyes. I'm thinking I'd be getting the recovery pump and tank out.
Its a 40+ year old 90 gallon milk cooling tank, the compressor is about a 1/2hp semihermetic similar to copeland, all the bolts and sump plug have gone very rust from bieng in a dairy for so long as its a packaged system. Was on R12 originally now on R49plus (R437A), it could do with the oil changing to POE but has been working like this for 5 years.
Had a choice of risking breaking the plug off to change the oil or leaving alone, chose to leave it.