In the Latin Church there is a pious custom, at least in the churches of the Slavic and Germanic lands, where the priest blesses chalk. We chalk each house (or the room where one resides) with the initials CMB (which stand for “Christus mansionem benedicat”, which also commemorates the 3 Magi), crosses (which are to scare the demons), and numbers (which signify the number of years that have passed since the original three kings came to Bethlehem).
 
The chalk is blessed, there is a special exorcism over the chalk. Done correctly, the house is incensed and sprinkled with holy water.
 
May the Magi intercede for us.