The hotter the better, but keep it below the point where your methanol will boil off, about 150F-160F.
When your wash water comes out clear, you have all the impurities out of the fuel. A small sample may take a day or two to clear if left open to the air. You can dry it immediately on a warm stove.
This comment has been crossposted at AT&T: 611 Folsom Street, San Francisco, CA -- Room 641A.
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