The You'll need to wait about 15 minutes after applying WD-40 for it to do its thing. For only slightly stuck stuff, it'll take three to five minutes. Some have even tried spraying sore joints with WD-40 as they would to fix a squeaky, door hinge. But this folk remedy is not proven to work and may even be harmful.
WD-40 contains petroleum distillates than can cause drying and irritation of the skin