My horns are mounted facing forward under my truck where the spare tire used to mount.
Last winter, during fresh snow they clogged with snow and if the temps were low enough turned to ice and had to crawl under the truck and chip the horns out.
I was wondering if I could fit some nylons from the girlfriends underwear drawer over the bells to keep snow out and NOT effect the sound of them or even some of the flexible type of window screen and zip tie it around each bell without effecting the sound??
You should be fine with window screen. That’s almost what the railroads use except theirs is a really tough nylon. I’m not so sure how well it does against snow. Amtrak and the like use pointed metal cones to deflect the snow.