Do NOT use a solvent based cleaner, as it could damage the integrity of the material. Rather, use alot of water and a cleaner that has a bleach ingredient. The use of a mild, non abrasive detergent will be necessary to cut through soil or any sort of mildly greasy or oily type film on the curtain. Test a small area first to make sure the cleaner you are using doesn’t discolor or ‘cloud’ the material. Using a cotton or microfiber cloth, wipe down the curtains in a consistent manner to make sure the entire curtain has been cleaned. Then use a clean, non-abrasive dry cloth to wipe down the cleaned area to remove water spots that could form and leave a residue.
Do NOT mix Bleach and Ammonia to use as a cleaner.
For safety purposes, wear eye protection and old clothing when cleaning your industrial curtains.