Do not pour fat, oil or grease down drains or garbage disposals.
Put hot grease and oil in a metal can, let it solidify, then throw it in the trash.
Use a paper towel to wipe grease off pans before washing.
Arlington County recommends keeping drains clean by pouring 1/2 cup baking soda down the drain followed by 1/2 cup vinegar. Wait 10-15 minutes and then rinse with hot water.
Please note that pipes that serve a single unit only (even those not visible from within the unit) are a unit owner responsibility.