You're lucky that you only get 60 of those backscatter/bounce messages a day. Somehow, an e-mail alias that I've never used started receiving those messages at a rate of 2 per minute, ~120 per hour. Thankfully, my system uses "maildropfilter", which I told to discard everything to that alias.

And the backscatter to this alias has not stopped for months. It's apparently some kind of new trick, I just don't see the point. Using my address to mailbomb every Russian server nonstop for a year?