To be more clear, 99% isopropyl alcohol, which leaves no residue. I have used it, and verified this for pretty much any spillage (koolaid.... OHHH YEAHHH)
Sorry, I was being lazy with my typing.
Isopropanol IS isopropyl alcohol, 'isopropyl alcohol' is the colloquial term for the chemical known as isopropanol, just as you might say 'ethyl alcohol' instead of 'ethanol'.
It's the 'ol' part that tells you it's an alcohol.
Either way, I'm pretty sure that sugars are insoluble in it.
Maybe it was simple mechanical action or displacement that helped remove the sugar when you used it.
It would definitely be best to do this before the sugary liquid has a chance to dry, because that would give the alcohol a better chance of washing it away.
Once it dries, you'd have the problem of insolubility and the alcohol would most likely not work to remove the dried sugar residue.
As I said, deionized water would be the most efficient solvent to use, but you are right that 99% isopropyl alcohol will evaporate much faster than water and leave little residue, though it will not dissolve dried sugar.
Bear in mind though that the remaining 1% is water (usually dionized), so it's still a good idea to leave it somewhere warm to dry completely before plugging it back in.
