Most flushes out there use Heptane and Isopropyl alcohol -- the former well used in gasolines, the latter is everywhere. Nasty chemicals.

I've done limited flushes using Denatured Alcohol (as a test) and it's a bit weak on pulling oil out of things even when "back flushed" (e.g. evaporators where a lot of oil, dyes, other contaminants end up)

 

The reason I would not use lacquer thinner besides what it leaves behind is it will hurt paint.
I used Prep - Sol (I had it on hand) it is used as a wax & de-greaser in doing body work and before auto painting and will not leave anything behind.
I only had to do the evap as everything else was new. The only reason to to flush the evap was it was open for about 4 years while I did the 4 year rebuild of the truck and it held psi before I took the system apart.
Other than a bad new O-ring that caused a leak that is all fixed now my AC blows cold.
Dave ----

 

I took this to mean "Brake Cleaner Fluid".. (Which I think is an acceptable solvent akin to Isopropyl Alcohol or Lacquer Thinner.

And for people that complain about people not using the search function:

There are SOOO many forum threads with dead links. There is so also a chance new information and Generally Accepted Practices can change over time.