I was working on a virtual test server with a very small (7Gb) C: drive, and the monitors were throwing alerts about low disk space. There weren’t any temp files, etc, that could be deleted to quickly free up space.  Tree Size revealed that there was a 3.5Gb file named modellog.ldf, which was clearly bloated comparing it to the other databases on the server.

I found this technique which quickly solved the problem: http://www.itbangbang.net/2010/06/how-to-shrink-large-modellogldf-file.html