The best rule of thumb is this: is you're not sure, then don't. Personally, I wouldn't bother cleaning it.
By cleaning the coin you would lower any value it may have by as much as 80%. I strongly suggest you leave it alone.
In that case, as in the case of almost all modern coins, its better off without being cleaned. I, for one, like the battleship gray tone that the florin has.
You can clean your coin - it's your coin afterall but that is if you don't mind the possible value of coins to plummet to ridicious prices.
