How to delete old attachments stored by Yahoo. mail ?

Hello,

Just found out that tons of old attachments were still stored even though their acompanying messages were deleted long ago.. Hundreds of them over several years.

Of course I can delete them on my Iphone 15 pro Max...but only one by one and it will take hours to delete all of them !!

Any idea of how I can get rid of them all at once ??

Thanks for your help.