I go back to the fact that few solvents are as good a Kerosene or Diesel fuel for removing serious grease and grime.  These fuels are somewhat dangerous due to the fire hazard (most solvents are flammable), but containing no high flash point solvents or super light hydrocarbons there isn't a vapor concern as with gasoline.  In truth, Diesel fuel is fairly hard to light.  When we used to set bonfires with it we'd use a tiny squirt of gasoline to make lighting it easy.  Trying to get it to light with just a match is not easy, and I highly doubt it would ignite from a spark under any conditions.  Diesel does have some lubricity to it, so its great for degreasing stuff that's caked with crud, but once it clean you then need to remove the oily residue of the fuel from it.  The newer ULSD is less so, because the parfins have been removed.  Kerosene is not very oily, often referred to as being "dry".  Be sure to wear gloves, safety glasses, and at the very least work outdoors, but preferably wear a respirator.  For disposal, run it through a filter and burn it as normal.  The junk in it would clog up the filter on a truck, tractor, etc., but oil or dissolved grease is certainly not going to hurt a Diesel.  Lots of guys mix a quart of oil, two stroke oil, etc. into every tank of fuel in their old Diesels because of lubricity concerns with the newer ULSD fuel.  A Diesel will even run fine on Kerosene, though you have to mix it with some kind of oil because it has no lubricity at all, but its common in developing nations, and even the military does it at times, cutting it with used ATF or motor oil from the motorpool.  FYI, various fuels for turbine powered aircraft are for all intents and purposes Kerosene. 

Even here in DE, as nationwide, most of the VOCs have been removed from the various spray cleaners like Brake Kleen, though Gumout 2+2 Carb Cleaner still seems to be the old formulation and works very well. 

Dawn and hot water do work well, be sure the water is hot though, because cold water will cause flash rusting. 

For paint prep and final cleaning lacquer thinner is still a good choice, though its also gotten harder to buy and might not be available in states like CA anymore.  Here I can no longer buy it at NAPA, but Home Depot sells it. 

After 60 years of hands on use of most solvents known to man including used dry cleaning solution my hands have developed an alergic reaction to anything resembling cleaning fluids. All it takes is a few drops of the stuff to make my fingers split right to the quick.
 I hope all you guys make sure to wear the proper hand protection when using harsh chemicals.

I use the cheap cans of brake clean or carb cleaner for stuff that's not too greasey that can be sprayed. Lacquer thinner from Home Depot does well for stuff that can be wiped with a rag. WD-40 and a soft bristled brush is my go to for the stuff that's really grimy and need scrubbing. Then a follow up cleaning to get rid of WD-40 and it's residue.

I use Kerosene for the same reasons other have mentioned.  As I understand, Kerosene is the base product in most commercially available de-greasers. I also use Dawn detergent for the final cleaning after kerosene use.
I also suggest using gloves while working with Kerosene.

TKOPerformance wrote:

Rudi wrote:

After 60 years of hands on use of most solvents known to man including used dry cleaning solution my hands have developed an alergic reaction to anything resembling cleaning fluids. All it takes is a few drops of the stuff to make my fingers split right to the quick.
 I hope all you guys make sure to wear the proper hand protection when using harsh chemicals.

Dry cleaning solution?!  Ack!  The improper disposal of dry cleaning solution has led to DE having its second EPA Superfund site.  Gotta believe that stuff is damn nasty. 
 

 
Dry cleaning fluid is or at least used to be perchlorethelene. It is a carcogen (causes cancer). I used it for years as a parts cleaner and to clean the garage floor. Today's dry cleaning fluid is not what it used to be. The land around my old shop in an undisclosed state is probably being declared a superfund.lol

Michael H. wrote:

6sally6 wrote:

In SC I still use lacquer thinner, acetone, MEK, naptha..........all the good stuff. Makes great hand cleaner too! especially acetone. Really promotes the healing process!
As far as disposal I have a couple of options..........(I live beside a "vacant-lot")  OR all the above burns great in my lawn mower!
I try to be an  unconscious citizen and recycle whenever possible!
6s6

All joking aside... can you really burn that stuff in your lawn mower?

YEP!!!!
Now I usually mix it 1/3 to 2/3 gas(or so) butt-eye have burnt all that stuff. That stuff you put in "Tiki" torches.....burns pretty good too!
Figger.........lawnmower engines are loooow compression so they aren't fussy about most anything volatile.
There's even a YouTube guy that burns ALL KINDZ OF STUFF in a lawnmower engine.
6s6

Years ago I started using denatured alcohol for a lot of stuff that I used to use other solvents for. Not as harmful to me or the environment. I also pour some in my windshield washer and it is wonderful cause I think I just had a Martini every time I hit the button!