<<Try www.acsource.com. The flush gun is the greatest , simple invention
yet.The power will be with you, and you will feel it when you pull the
trigger.Use mineral spirits,or a/c flush . The a/c flush costs about $40
a gallon. Thats got ripple beat. It took 2 gallons to do my westy-of
mineral spirits , that is.>>

You want to know a secret?
Use alcohol instead of the mineral sprits.
The alcohol will dry up any moisture in the system real good as well as
clean it out of any snot in the condenser / hoses / evaporator / dryer.

Run it in one way, then reverse the direction.
Clean it both ways, you'll be good as new.

The only reason I'd be afraid of using mineral spirits is it doesn't
suck up any moisture, and it will leave an oily residue behind.

And you surely don't want to do that.
It might contribute to more dryer  contamination / failure.