pcv valve, how to tell if it is bad

[coffeedart67]

How can I tell if my pcv valve is bad? I put pre 67 valve covers on my 67 273 and have to use that cap with the metal pcv. I have 2 of the metal pcv's both used and will reuse one of them, until a time I can find a new replacement.
Thanks
Aaron

 

[daredevil]

Not very scientific but I always shake them to make sure they rattle.

 

[tekslk]

x2 if they rattle there good, if they dont try soaking in solvent over night.