Yes, so long as you clean it well, and it's large enough to hold your water. I assume you're talking about a large Dutch Oven style pot . . . I can't imagine what else would be enameled.
That being said, if the enameled coating is cracked, or looks off color, I might not use it.
Truth is, a good turkey fryer is cheap, and usually comes with a good aluminum pot that works wonders, if treated properly (remember, never use your aluminum brew kettle for anything other than brewing!).
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