Gmail empties messages from the Spam folder every 30 days. This used to be fine for me as I was only getting a spam email every couple of days, which didn't particularly build up over time. I'm now getting between 5-10 emails a day which are filtered to my spam folder. This would be fine, and I'm happy that Gmail does filter these out pretty much bang on each time, but the Spam folder is highlighted whenever there's unread emails in there, which annoys me somewhat.
I'm aware you can manually go into the Spam folder and delete everything with a single click but is there a way of changing the time a message will stay in the spam folder before it is deleted?