Commercial low impact cardio machines such as stationary bikes and ellipticals contain Sealed Lead Acid (SLA) batteries that should not be thrown away but recycled properly. This video shows you where to go with them, Batteries Plus may take your batteries free of charge. They will send them off to be recycled and make sure there is no danger to the environment. A sealed Lead Acid Battery in the ground over time will decay and leak its contents which are toxic to mother earth. So! Try Batteries Plus Inc. or a "like" retailer if your looking to get rid of any Sealed Lead Acid, Lithium Ion, or AGM Battery.
Resource: Here we talk about Battery Testing and replacement. https://youtu.be/wM4vzyIN2Dk