If you go to any auto parts store, such as Auto Zone or PEP Boys, you'll find cans of spray chrome paint. The last time I used it was decades ago, but, if I remember correctly, the prep was rather simple: cleaning, masking, primer, and spray. I don't know how well the paint would hold up to salt water, assuming youi're boating in salt water. Replacing the drain with real chrome-plated drains is another option, though rather expensive. Hy