'01 SXR500 loose screen rattle in exhaust can??

[snowmanhat]

have a rattle on the exhaust side of my '01 sxr 500 when I give it the gas - it's driving me crazy. Not loose disc on brake, not clutch cover pin and not exhaust springs although it sounds like a vibrating spring.

Thinking loose screen in exhaust can - how do I fix?

Has anyone else had this problem? Please help

Thanks