Grease is made of fat, oil and grease. When this mixture enters the drain it gets harder to clear them out with water because they form layers for each other. The best way to get rid of grease from your sink or shower head would be to use boiling hot water which melts down the fat and oil in clogged drains. Pour a pot of boiling water down the drain and wait for it to work its way through. If that doesn't work, pour half of a bottle of baking soda mixed with hot water into the clogged drain. Follow up by pouring in one cup of vinegar. Cover the drain with a plug or cloth and let the mixture sit for 30 minutes. After that, pour hot water down the drain. If the clog is still present, use a plunger. If that doesn't work, it might be time to call in the professionals.