A/C rattle?
 

So I was at idle today and I noticed that when the a/c was on I could hear a rather loud constant rattle. As if you took a plastic bottle with a marble inside and let it rattle about.

I had A/C work done about a year or two ago....I don't really remember if the car sounded like this prior to the work. (on the compressor i presume)

Does anyone else notice their A/C sounding "rough" or "loose" at idle?