Last season, I purchased a couple of spares that I did not end up using until this season....
They did not sound good "out of the package" and I just figured it was inconsistency in the call....
When I went to clean the calls, and separate the reeds with a plastic fork tine, I had tremendous difficulty separating the reeds. I used dish soap to work the tine in and separate the rubber (and of course rinse under water with the tine in between the rubber). The calls sounded much better after this process...
In generally, I pull them from the case and call... If they sound good I will use them as is... If they do not sound so good, I will attempt to separate the latex as just mentioned....