Help to identify location of sweat and how to handle it.

I sometimes have that a few days after its been raining, I put it down to residual moisture in the road grime, though I have never really worried about it. If it's persistent after a long dry spell then make sure everything is as clean as possible and observe for reoccurrence, that would then give some idea of what kind of fluid it is ,oily, greasy, watery etc.