I play around with the spices in my preserves, Jeffie. I don't always use the same combinations...(I do document this, so I know if it turns out to be a particularly lovely, or nasty, batch, I'll know what changes I made). Cloves are not a vital necessity...they simply have their unique flavour. If you don't like cloves, or are allergic to them, you can remove them and replace with, say, a touch of anise? for something different? I don't know the specifics of whether cloves were originally included for any preserving purpose...or whether it was simply for flavour.
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Here's a wonderful place to check out for spices. They have catalogs they can ship you and do on-line orders.
http://www.penzeys.com/