We had a few old mobile phones, including two pre colour models, which were just taking up room in the house. You know the story - "I'll keep it just in case."
Then we found bags at the Post Office that you can use to donate your old phones to charity.
Any phones that are useable are sold second hand and those that are not provide spare parts. All we had to do was pop the old phones in a bag (without the charger) and drop the bags in a post box.
Job done and a little bit more space in the house to fill with new toys.
PS Of course, if you have incriminating messages and photographs stored on your phone, it's probably best to remove them first!