The machines may not be running, but you need to monitor and maintain your metalworking fluid anyway. A production stop, triggered by a virus or anything else, may also be a good opportunity to clean your machines and fill them with new coolant. 

Chemistry and microbiology continue to be active in your water-miscible metalworking fluid even when the machines are not running. The fluid doesn’t circulate anymore and there’s no supply with fresh emulsion. All this can lead to severe problems such as bad smell, corrosion of machine parts and splitting of the emulsion. You therefore need to decide whether you maintain your coolant during the production stop or whether it’s a good opportunity to dispose your old coolant, clean your machines and get them ready for future production.

Water-miscible metalworking fluids cannot be left on their own. They need to be monitored and maintained regularly to ensure the stability of the emulsion. Cutting and grinding oils do not need any specific precautions. However, the production stop may be a good opportunity to clean the machines and change to a new oil.