SMPs not deleting user state as configured

We have CM2012 SP1 R2.  Some of our SMPs are running out of space.  They are configured to delete user state data after 14 days but I see in some cases there is older user state data sitting on the SMP taking up space. 

First question is why is the user state data not deleting after 14 days as configured on the SMP properties?

Second question is, is it safe to delete these folders manually?  Or is there a better method to "clean-up" the old user state folders?

Thanks much!

FP