You can spread it on parchment paper (paper butter wrappers work), put it in a dehydrator until is dries out completely, then scrape it off the parchment into a jar or plastic bag. It won't be sour cream exactly anymore, as the lacto-bacillus will be dead, but it will work. You can do the same with yogurt or buttermilk. You can do this in an oven if you can keep the temp at 110 to 120 degrees.
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The ultimate result of shielding men from the effects of folly is to fill the world with fools.
-- Herbert Spencer, English Philosopher (1820-1903)