My skirt froze in once, took an hour to free it. Next day picked up a bag of sand from hardware store and put together sand socks.
- large ziplock freezer bags
- measured out 5 lbs of sand, put in freezer bags
- rolled bags close, sealed, wrapped tape around each end
- placed inside old wool sock, tied knot, cut off excess leaving about 1.5 inches
- put inside second wool sock, knotted end of first one in first
- knotted second sock, cut off excess leaving 1.5 inches
Have 6 of them made, all fit inside milk crate that goes on the bike, no problem since.