Color of the day: Black
Incense of the day: Sage
Start by doing physical cleaning. Dust anything sitting on the altar, maybe rearranging or adding things if it no longer feels quite right. Then take some incense (citrus or rosemary is good ) or a sage smudge stick and waft the smoke around the altar to clear away any lingering negativity or stagnant energy from the winter. Sprinkle a bit of salt and water and say:
"This altar is cleared and cleansed
for another season of positive
magical work. So mote it be."