Stupid question....

[momtoallmybabies]

Has anyone ever used Clearblue Easy (OPK) test sticks after they've expired and still had accurate results? These things are so expensive and I've found a monitor someone is selling that comes with 30 test strips but they expired! Several people have mentioned that it is just litmus paper and therefore should still work fine. Does anyone have any idea if this is correct? I probably shouldn't use them right? Just go buy new ones?