Motor Oil In Alternator/How Do I Clean?

[2001GTPEWTER]

Don't ask me how this happened (it was a mistake of my own, not a fault of the engine) I spilled a little motor oil on the top pulley of my 2001 Mustang GT, some of it got in the alternator after running the engine a few times, now whenever I turn the engine on I hear this loud hissing from the alternator. The car runs fine, no overheating or smoke, but starts in the second turn of the key, not the first. And of course that loud vaccum-like sound. Whats the best way to fix this or will I need a new alternator? For reference the engine is stock except for a cold air intake that I attached.