Doing a Liver Flush Tonight and Have a Question

My husband and I both finished a month of Humaworm a week ago. We are now doing a plain Liver Flush (from the Humaworm website) tonight and I have a question. Some other websites say that if you don't do a Colon Cleanse first, stones will get stuck in your colon on the way out. Is there any truth to this or are they just trying to sell something? I have noticed that the sites that say this are selling Colon Cleanses so it makes me wonder...

The humaworm we took had psylium in it and a lot of stool was passed during that month on it so I'm not even sure if a Colon Cleanse should be an issue anyway. Any advice from someone who has done this before?

Any help will be greatly appreciated.