Yes Toner cartridges can be recycled. There is often a charge as there is very little commerical value in empty toner cartridges.
RECYCLED
Where?
If you have genuine cartridges you can recycle them through these schemes.They need to be the same manufacturer of the scheme you are using. So only send HP cartridges through HP's scheme for example.
If you are unable to find a solution through these companies then please try the following organisations;