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Parts Washer Solvent

My partner at my shop just bought a parts washer from a school system that eliminated their Auto shop program.

What are your recomendations on a brand solvent that you prefer.

Thank for the input.

I haven’t tried this but have seen some reviews saying it works well as a parts washer:

It’s water based and safer than petroleum based products.

Dealing with the politics of chemicals used for cleaning parts in a shop is a tough row to hoe. Several products advertised as biodegradable are not as easily disposed of as their ads indicate. It might be advisable to check with state and local environmental agencies to determine what you can safely and legally use and how to dispose of it. I found a petroleum product that worked well and could be disposed of with my waste oil but the brand name escapes me. Be care though. It may cost considerably more to dispose of a barrel of old cleaner than it cost to buy it in the first place.

I discovered mineral spirits some 20 years ago. That’s what I use and it does a great job. It’s not as powerful as some other chemical cleaners but it works better than water based products.

Unless the parts washer is heated, water base solvents aren’t very effective in removing grease and oil.

I’ve used this in my parts washer for years.


The “green” solvents may start out bio-friendly, but they end up loaded with the oily gunk and grime that was washed off.

I like mineral spirits with ~25% lacquer thinner to make it a bit more aggressive.

Another vote for 100% mineral spirits.

Where do you live? If it is Cali, you may be forced to use water based cleaners.

Mineral Spirits

The standard solvent for parts washing is called “Stoddard Solvent” It’s very close to mineral spirits on the inflammability and safety scales…The problem is, what do you do with the used solvent after a few months of use? It becomes a MAJOR disposal problem. Commercial companies like Safe-T-Kleen will service (change the solvent) for a price…

A few months? The last batch I had lasted something like 8-9 years. The only reason i disposed of it was i was moving across country and didnt want to move it. It doesn’t go bad. Every once in a while I let it settle out and drain off all but the sludge layer. I clean that out and return the 90% I saved and top off with new. The sludge I put in an old container. After a year or two its full and that container goes to the twice a year hazardous clean up event provided by my town.

@‌Twin Turbo

I agree. My parts washer has a sludge tray.

Drain the washing fluid. Pull the sludge tray and dispose of the sludge. Same as disposing oil.

Put the parts washer fluid back into service.


With use, the solvent becomes saturated with dissolved grease and oil. The parts you are trying to clean just don’t come out clean anymore…How long the solvent lasts depends on how much you use the parts washer…

Well, all I can say is that the solvent becoming “saturated” with oil and grease is not my experience and I restored at least a half dozen classic cars using that solvent in addition to normal repairs. YMMV.

I’ll bet not many of you remember the “good ol days” when the de facto cleaning fluid for carburetors and electrical componenets was carbon tetrachloride.

Thanks for all your input, and Francizek…I remember carbon tet.

I researched the various brands and recomendations that reviews showed and reported my findings to the guy who bought the unit.
Turns out it rests on a base of a 55 gallon barrel with the top cut off and uses water with a solvent added. A heater heats the fluid to around 130* and the pump draws from the middle portion of the tank, while the heavy crud sinks to the bottom and the lighter matter floats to the top layer.
I don’t know if this will work for us because we are not a shop where the heat stays on when we are not working. I’m actually the only one who works on vehicles that are not my own and at times that can be sporatic. Sometimes neither of us has work and the heat in the winter is shut off for days at a time. We might have to rig something to keep this from freezing unless the solvent acts as an Antifreeze too.
I’ll have to check this thing out closer and figure out if the heater heats all the fluid or if it heats only the fluid being pumped up to the cleaning nozzle and brush, heating it on it’s way.

I never heard of using Mineral spirits so I guess I learned something thru all this. I always used a little kerosine in a drain pan and a brush the few times that I have had to clean that much.

Thank again for all the input.

Then, of course, there is/was “Cold Parts Cleaner” generally used on carburetors and transmission valve bodies…Truly nasty stuff, take your skin right off…Trichlorethylene based maybe? Almost impossible to dispose of safely…Came in a 5 gallon can and had a layer of a second liquid floating on top of the solvent to keep it from evaporating…Parts came out looking brand new…

Trichlor was used extensively in vapor degreasers to clean the flux residue from PCBAs after the solder wave. Nothing worked as good then or since but…

Most places ran the vapor units non-stop with the covers off even if no boards were being cleaned. The key word being VAPOR. When Trichlor vapor is combusted, it results in a nasty acid. Back then, people smoked cigarettes inside the shop. Quite a few ended up with some form of cancer. Was it related? Tough to say. However, one place I worked at moved into a brand new building. Two years later, the HVAC venting ducts were rusted out so bad they were falling to the floor…

TT, if air conditioning ducts are un insulated, and go thru un conditioned air, even the hot ceiling of a conditioned space, large amounts of condensationwill form and the ducts will rust out very quickly


If the parts washer uses a water base solvent then it can’t be stored in an unheated area as it will freeze. Unless you keep the heater on all the time and that isn’t cheap. Or you’ll have to add an antifreeze to the solvent such as alcohol but the that would have to be replenished because it would evaporate off in an open system. And you don’t want to add glycol to the solvent as the parts would come out with antifreeze covering them.

And since this is a water base solvent parts washer, you can’t use use regular parts washer solvent. The wetted parts of the pump would be destroyed by the solvent. So if you decide go with regular parts washer solvent, the pump will have to be replaced that can handle the regular solvent.