Hi All,
I have access to vermiculite used to over pack bottles of chemicals.
Can I use this as a soil amendment in my Zone 4 clay soil? Also would
it be good to add to potted plants? The material is clean, dry and I
have Material Safety Data Sheets from the supplier that says it is
non-hazardous and asbestos free. Please advise. Thanks in advance.

I think it would be fine to work into your clay soil to help open it
up. It isn't going to provide any nutrients, of course, but your soil
might be healthy enough already. I don't know about adding it to
potted plants, for the reason that it doesn't hold nutrients and potted
plants need all the good rich potting soil they can get.