There was a bit of ice in some sap buckets. The filter bag held it just fine. The frozen sap will eventually melt. If the elastic gets tired, it may need a small cord tied tightly around it on the neck of the barrel to keep it in place. The paint filter bags you buy might not have such a good elastic. We used to use our dairy milk filter just because we have it. Those are expensive to buy just for collecting sap. I do not recommend cheese cloth or any other natural material. The sugar seems to cling to them. Nylon is not only stronger, it filters better.