We've created a bot for Telegram which uses the JSE captcha to prevent spam.

https://jsecoin.com/telegram-spam-prevention-bot/

Invite @jsetelegrambot to your group (requires admin). If anyone runs a group or is a member of a community that has a problem with spam then please help spread the word. It's a good way to add value and get the project in front of a tech savvy community on Telegram.