Cleaning compositions for use in closed loop cleaning machines

A closed loop cleaning process, comprising:

• loading an article to be cleaned into a cleaning chamber;
• closing the cleaning chamber;
• vaporizing a non-aqueous cleaning composition into a non-aqueous cleaning composition vapor, where the non-aqueous cleaning composition includes at least about 85 percent by weight organic solvents, based on total weight of the non-aqueous cleaning composition, and where at least about 5 percent by weight of the organic solvents is propylene glycol, based on total weight of the organic solvents;
• directing the non-aqueous cleaning composition vapor into the cleaning chamber;
• condensing the non-aqueous cleaning composition vapor into a liquid on a surface of the article, to clean the surface of the article;
• collecting the non-aqueous cleaning composition including contaminants from the article;
• recovering the non-aqueous cleaning composition via distillation from contaminants in the non-aqueous cleaning composition, where a distillation apparatus removes the contaminants from the non-aqueous cleaning composition;
• and
• recycling, by a process stream in the closed loop cleaning process, the non-aqueous cleaning composition recovered via distillation back to the closed cleaning chamber.