Cold temperatures are not your friend if your M26 and M12A1 decons sit outside for long periods. In freezing weather, you should protect them.
It’s almost impossible to drain out all water from the M26 and M12A1s. That water can freeze and damage things like tanks and pumps, which are expensive to repair.
Stop cold in its tracks like this:
For the M26, freeze protection is easy. Just run antifreeze through it. Follow the Measures for Storing and Frost Protection in Excess of 30 Days guidance in WP 67 of TM 3-4230-238-23&P (Nov 09, w/ch 1, Dec 12).
For the M12A1, follow the Operator Maintenance Operation under Usual Conditions instructions in WP 11 of TM 3-4230-237-10 (Jul 12). If the M12A1 is going to be stored for less than 24 hours, follow Step 1. For 24-48 hours, follow Step 2. For more than 48 hours, follow Step 3.