I asked the nice people at Molbak's in Woodinville the same question two weeks ago. The advice I got was mixed but many people seem to be pleased with their results from using the repellants with castor oil in them. Moles don't like the castor oil and it's not toxic for your soil. However, one helpful Molbak employee told us that she had spectacular results from collecting the "doggie dumplings" from her yard and inserting them into the tunnels. She said, "The moles leave because they don't like it!" My reply, "Wouldn't you, too?"
Best of luck
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