I've been running the "infusion" program at the bar where I work for about the past year and a half to two years. My best advice is to use small mason jars so if you screw something up then you aren't wasting a full handle of vodka. Err on the side of safety and be sure to refrigerate your infusions that use "soft" fruit and foodstuffs as well.

I would also agree with colorider, canned fruit is generally going to be waaaaaaay too sweet. If you're just trying to get rid of the vodka and some canned fruit, try draining and washing the fruit first, then be prepared to mix the vodka with something like iced tea or a really tart lemonade when serving. Also be sure to cut up the fruit, the more surface area the fruit has to interact with the vodka the better.

PS, when infusing fresh pineapple, the core (which is generally discarded) will lend the most flavor.

PPS, If we ever have a decent crab apple harvest again, then try infusing a "sharp" rye whiskey (bulliet rye works well and is relatively cheap for a handle) with crab apples and then use that infusion as the basis for an incredible Manhattan

feel free to pm or reply here if you have any other questions.