A couple of years ago, a yarn supplier told me that a drop of baby oil would oil ,and waterproof wool. I tried it, and it has worked very well for me on a large number of swatches and objects. I have repeated the advice often.
I now find that the situation is more complex, and the baby oil was acting a carrier for other materials with which I inadvertently contaminated the yarns and/or objects. Thus, the waterproofing that I see in my knit woolens requires more than just baby oil.
Other materials in my crafting environment which may be causing the effect include:
• Spinning oil on a yarn that I frequently use
• Bees wax,
One, or all of these, is likely contributing to the weatherproof qualities of the objects that I make.
In any case, my weatherproof fabrics are not noticeably oily or waxy, nor do they smell like sheep when wet. Thus, I am taking bout trace quantities of contamination. The advice to knit very tightly, full completely, and oil the wool stands. The ambiguity is what “oil” is best.
Anyway, I am sorry for any confusion or problems that this may have caused.