If you have any old used toner cartridges, rather than throw them away, why not send them to Recycle4Charity?

If your register on their website, you can nominate Cats Protection Camberley and District to receive the funds raised and they will even send you a Freepost envelope to send the toners back to them.

If you work in an office, perhaps you could ask your employer if they would like to join the scheme?