Baseboard Cleaner! First vacuum around them, then use: 1/4 cup of fabric softener 1 gallon of water A microfiber rag With this method, you can easily clean any leftover dust or grime and repel any future dust since the fabric softener naturally repels static electricity (which attracts dust).
Get a jump on spring cleaning with the Baseboard Buddy ($19). Not that we're looking forward to doing a deep clean of our apartment (kill us now, please), but we love us a clean space. Anything that helps us.