Don't open the phone (except to take the battery and cards out). Buy a quart of alcohol - it's only a buck. Soak the speaker in a few ounces of it for a few minutes. Swish it around to get any loosened pieces out. Toss the alcohol, shake and drain the phone. Put more alcohol in whatever container you're using. Do it all again. Dump and refill one more time.
Even after drying for a day, that should clean it out pretty well.
Once you've done that, read
Wet Phone. Putting a wet phone in rice is one of the 4 things you DON'T do. (Not until you've cleaned and dried it with alcohol.)