Battery is knackered, DON'T go anywhere near electrical items with SANDPAPER, the glass particles that rub off the paper can melt on the item being sanded when subjected to electricity, and insulate the terminals!!
My friend did it with his SKODA RAPIDE years ago despite my telling him not to use it on his points, broke down 15 miles from nowhere at 3am, towed car back I cleaned the points started frst time!
tabetha