Use a razor blade to scrape as much of the stain from the siding as possible.
Fill a bucket with soapy water and scrub the stain with the rag.
Spray the stain with multipurpose remover. Allow the remover to sit on the stain for several minutes and then scrub it with another rag (not the one you used in the soapy water).
Rinse the stain with plain water. If you can still see part of the stain, repeat Step 3 until the stain is gone.
Use a razor blade to scrape as much of the stain from the siding as possible.
Fill a bucket with soapy water and scrub the stain with the rag.
Apply mineral spirits to a clean rag and scrub the stain with the mineral spirits. Do not allow the spirits to sit on the stain, but start scrubbing right away.
Rinse with water as soon as the stain is gone. If the stain is not gone, repeat Step 3.