Parts Washer Solvent
 

I know there are many threads on solvents (too many probably) but I have not seen anyone comment on using Zep Heavy Duty Citrus Degreaser?

ZEP 5 gal. Citrus Degreaser-ZUCIT5G at The Home Depot

I don't have direct experience with that one, but have with some other water born solvents. If your shop isn't heated, around here it would be a problem with freezing. Plus, those tend to work much better heated to warm at least. And you need to do something with the parts after to make sure they don't rust. Mineral spirits tends to leave enough residue behind that things don't rust. And don't think that you can just rinse the Zep down the drain when you are done. It's not just the degreaser, but all the stuff that you degreased that shouldn't go down the drain. I know some folks use the water born mixes with success, but I don't know any of them.

My other option is psc1000 from tractor supply

Crown® PSC 1000 Parts Cleaner, 5 gal. - Tractor Supply Co.

My buddy has an old solvent-tolerant parts washer and uses diesel. It works quite well. Not for everybody though.

A good friend of mine has used diesel in his parts washer for years, it works every bit as well as Stoddard solvent and when it gets dirty he uses a 12volt pump and sucks it out, pumps it through a spin on filter then stores the dirty diesel until winter where burns it in his torpedo shop heater. Nothing is wasted.

I have always used plain old solvent,varsol,mineral spirits which ever is on sale when I need to replace it ,

Ne too. It seems like I smell deisel on me forever even if I wear gloves if I go that route.

I use kerosene, a little more refined than diesel and less smell.

The water based cleaners work very well for most things, but won't touch baked on grease. Only solvent will.
I have a low odor mineral spirits in mine, but it does evaporate over time. I only use the washer if I'm rebuilding an engine though.....