I only made the comment because I once bought a stock my broker described as "thinly traded." There was some kind of market crash in the mid '80s, and the class of stock I owned simply disappeared. Ultimately, E.F. Hutton bought it for $1.00. This is a sometimes courtesy that lets the owner of valueless stock take the tax loss. You can't take a loss on a stock you can't sell because you still own it.
For what it's worth, Publix is a much better developed company than Noble Metals Recovery. I know nothing bad about it, but do encourage you to diversify, just on general principles.