How to determine fiber content?

I have a box of yarn sitting here that I bought off ebay years ago for weaving. Of course none of it is labeled, and it’s been so long that I don’t remember what they are. I have long since sold my loom, so was thinking about knitting with some of them, but am not comfortable doing so unless I know what the fiber is.

I am almost positive none of them are wool, they are probably all cotton, or manmade fibers (poly, acrylic, nylon, etc.), or blends, possibly with some silk tossed in.

Anybody have any suggestions?

If you google ‘fiber+burn test’ (or similar) there’s lots of info. As all will state BE VERY CAREFUL. But it’s quite good in narrowing down what you might have. Some have good pics of the burned fibers for comparison.