Prism, I spent about 8 hours removing WD-40 from inside a vintage Bernina once. What a terrible chore. I do service machines to earn $, so spending 8 hours cleaning out gummy workings or even one hour removing WD-40 is completely unnecessary when there are wonderful products on the market. Sometimes I have to let the Triflow seep in over night to dissolve or break through locked machines, but it's the go to product for most techs.