It’s better to segregate toners from dry mixed recycling waste. Toner and ink cartridges can be reused and recycled into the same streams present in DMR, however the residual ink and whether or not the cartridge is damaged complicate the process and make recycling and reusing them more difficult.
With a specialised toner recycling service, the cartridges are cleaned out if they are undamaged and then simply reused, however if there is any damage then they need to be broken apart and then broken down into reusable materials. If they were thrown in a regular recycling bin, none of the toner cartridges could be salvaged for reuse.