Hello...welcome and thank you for using Justanswer.
The greenish color you see is from an ac system leak ,his is Freon most likely with dye that we usually use to check for leaks with special light (uv light)
I would check the AC system performance ,make sure the pressures are good (low pressure around 35/45 and the high pressure close to 200 psi,depending on the temperature where you are)
The code P0442 it is for a small evap leak detected , I don't know what did they smoke on the system ,beside the fuel tank ,canister and the hoses/lines ,there are also the purge and vent valves that need to be tested for proper operation ,they need to open and closed when commanded by the engine computer when running the test on the evap.
One of the most common small leaks is the fuel tank cap ,you can just buy it and have the code erased then drive the vehicle to see if the problem is solved.
Other possible causes are the hoses at the fuel tank neck ,evap canister or the hoses to it ,fuel pump gasket or a rusty fuel tank but to check this you will need the smoke machine.
Let me know.