According to http://wiki.openstreetmap.org/wiki/Map_Features, the sand box seems to already exist. “amenity=grit_bin”.

If we would like to include all kinds of winter maintenance I can add heat to salt/snow plow/gravel/sand. In some cities in Sweden radiators are placed under some central pedestrian streets’ surface and the surface is heated above the snow’s melting point. These pedestrian streets are therefore always snow and ice free.