Dampen a clean cloth with water, and wipe around the seal of the door to remove any loose dirt or debris.
Mix a weak solution of one part chlorine bleach to 10 parts water.
Dip a clean cloth in the solution and use it to wipe the seal. For harder to reach dirt and grime, use an old toothbrush dipped in the solution.
Rinse the seal with a clean damp cloth to finish removing any last bits of grime.
Wipe the seal dry with a clean dry cloth.
Allow the door to remain open for at least half an hour to let the seal finish air drying.