I often see dangerous sun filters on sale on Ebay with 1960/70s scopes, you know the eyepiece type.
I always write to them asking if they can please destroy the filter before selling the scope and send them this link.
https://www.youtube.com/watch?v=fjshhNbSlCs
Here is a reply I received today, I have never not received a thank you.
Hello Jeremy,
Many thanks for the information. I have ended the listing and will relist once we have excluded any dangerous parts.
We appreciate you taking the time to help us.
Kind regards
Melanie
On Behalf of the Willen Hospice eBay Team