It is, of course, impossible to tell you anything about your "pearls" without seeing them in person, but I suggest you take them to a jeweler or someone who give appraisals and they should be able to help you. They could be just about anything from artificial pearls to cultured pearls to natural pearls. It's a wonder sometimes what people throw out....but you'd have to have an expert look at them.
Maybe by now you have a camera so could take a photo or have had someone look at them. I'd love to hear any updates you have.
Thanks for sharing your find on my site and please let us know what you can find out about them.