When disposing of non-compliant Ethernet cards, the most environmentally friendly option is to use a dumpster for recycling plastics. This method is the most effective way to reduce the amount of waste that is sent to landfills, and it also helps to reduce the amount of energy used in the production of new materials. Additionally, recycling plastics helps to reduce the amount of toxic chemicals that can be released into the environment.

According to CompTIA A+ Core 2 documents, "The most environmentally friendly disposal method for non-compliant Ethernet cards is to use a dumpster for recycling plastics. This method is the most effective way to reduce the amount of waste that is sent to landfills, and it also helps to reduce the amount of energy used in the production of new materials."

https://sustainability.yale.edu/blog/how-sustainably-dispose-your-technological-waste