All solutions sold by Vernier are shipped with a SDS (Safety Data Sheet) which describes disposal considerations. If you have misplaced a Vernier SDS, you can download it at
https://www.vernier.com/tech/manuals.html
Your own state and local regulations should also be consulted.
In general, the Flinn website provides an excellent guide for safely disposing of most solutions. Here is the link: https://www.flinnsci.com/msds-search.aspx