Volvo: Engine turns over but will not start., metal surfaces, sandpaper

Question
This has been a problem that's been getting worse and worse.  I turn the key, and the engine turns over and over, but it won't catch.  I've got a 1989 240 DL and this was the same problem with my previous volvo which was a 1976 240 and the mechanics could never figure it out.  Any help would be appreciated as my car is parked at work.  

Answer
I had this same problem with my 1980.  What it ended up being was corroded contacts on my ignition coil.  They are exposed to the elements, and tend to get gunked up.  I would run cleaner and sandpaper over all exposed metal surfaces in that area and see if that clears it up.  Good luck!