Black sludge can easily build up in the drain of the bathroom sink from mold and mildew development, as well as toothpaste and other particles you rinse down the sink and thereby allow to accumulate in the drain pipe. A moderately easy process, cleaning away the black sludge will take care of the blockage and leave your sink draining properly.
Cleaning ur stove air vent. Put them outside on top of paper bags. Spray an even coat of easy off oven cleaner on one side. After a hour or two turn it over n spray even cost. If really yucky, repeat a few times. Next day, take to kitchen sink, with warm water n a soft scrub sponge wipe edges. With hot water spray the vent and watch all the yuck go dwn the drain. Let dry. Dont forget to clean sink afterwards.