IF your state (like California) or your local political entity mandates LIPO battery disposal methods, you must follow their rules. Some companies accept drop-offs.
If there are no rules where you live, defective LIPOs can be disposed of as follows: In a plastic bucket outside the house, dissolve ordinary salt in warm (not hot) water until no more will dissolve. Place the defective LIPO into this salt water and leave at least 24 hours. Remove the battery, and if you have a voltage test meter, you can check that the voltage is now zero. This LIPO can now go into garbage; LIPOs with no electrical charge are generally considered not harmful to the environment, although some authorities do not agree.