"Fine sand" refers to a type of small-sized grains of sand that feel smooth when touched. It is a soft and powdery texture found on beaches, used in sandboxes, and sometimes for building materials. Full definition
Beautiful beaches with fine sand stretches between steep mountains and the majestic sea. (lapointcamps.com)
I have taken the panel off and cleaned all the contacts for the fan control (with a bit of very fine sand paper) but it didn't seem to help. (mechanics.stackexchange.com)