Most times the Evaporator isn't all that dirty inside unless a compressor has come apart and sent metal through the system, but a good idea as you know to clean it out. I would use the local auto parts store "Flush" for A/C systems instead. Just in case the Acetone wants to "Attack" the aluminum for whatever reason..
Make sure you kinda blow a little A/C (PAG) oil through it to help protect it until ready for use if it's gonna sit any length of time. Also, make sure you cap off the ends really well..