I'm with the UNIX old timers on this one; cleanliness is overrated. Life is messy, creation is messy. More uptime means more mess. Uptime is longevity; there are few things more valuable in life than longevity.
Every now and then I might take the time to sweep through and nuke them all, but that might take months or years.
Years ago my cube-mate was called to support a desktop user who has having problems with their machine that couldn't be fixed remotely. He realized the user's HDD was full, so the first thing he did was clear the user's trash bin. Mysteriously the machine came up with a ton of free space.
The user seemed happy their machine was up. Nor long after, the help-desk called my cube-mate asking what they did to the user's machine; The user couldn't find any of their files that they had organized in the trash bin.