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Call a plumber.

Article:
If your clog persists after you have tried multiple natural unclogging methods, you may need to contact a local plumber to assist with your clog. Let the plumber know what methods you have already tried to unclog your sink so that they can avoid using products that may cause a negative chemical reaction. Check local listing online or in the phonebook to see if there is a plumber near you that is environmentally-conscious.