Hi Allen,
As far as wheather to use liquid or solid vegetable oil - it really doesn't seem to matter.  Dr Wilson at USDA used solid vegetable shortening while most beekeepers here now use liquid vegetable oil.  As long as it is all vegetable oil is really doesn't seem to matter.  Both will increase the surface area for the menthol to evaporate from greatly thereby greatly increasing the rate of evaporation.

Not sure on your dose question.  Have not heard of any testing in that area.

blane



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Blane White
MN Dept of Agriculture
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