Where P501 is required for a plant protection product (PPP) ('highly recommended' or 'recommended' depending on the product's physical properties, human health and/or environmental hazard classification) the phrases to be used on PPP labels are as follows.
For all professional products
Dispose of contents/container to a licensed hazardous-waste disposal contractor or collection site except for empty clean containers which can be disposed of as non-hazardous waste.
For all amateur products
Dispose of contents/container to a Household Waste Recycling Centre as hazardous waste except for empty containers which can be disposed of by recycling. Contact your local council for details.