Knitting wool - Acrylic or wool

I have some wool I want to sell, but am not sure if it is wool or acrylic. I know there is a method of telling, one is putting a little bit in bleach, but what happens to it to know whether it is wool or not. If there is another method I would appreciate know it.

Try burning it, if its wool it smells like burning wool & sort of singes, if its acrylic it melts & usually sets in a hard ball.

Burn the end, wool won't burn but acrylic will........get a young firefighter in full uniform to be on standby!!

Try to break it between your fingers - wool will usually break with a bit of pressure, acrylic should only stretch.
You should also be able to tell by its touch, and often colour. The acrylics tend to have more vivid colours and have either a very acylicy feel, or extremely soft.

I assume there are no labels to give us a bit of a hint ???