@ aakaakaak-Rinse the heck out of it. That's just about the only advice there is. Basically, stick it in a bucket and stick a hose in the bucket. Turn the hose on full blast and sit there stirring the sand and dumping some of the water until the water runs clear. Takes for freakin' ever!! I will never use play sand again because of what a PAIN it is to clean.
@ freash_water_fish-Did you get three angels in the hopes that two would pair off and then the third would be returned to the LFS? Because, honestly, if you're thinking of keeping the third angel if two pair off, you're going to need another tank or you'll have World War III. Breeding angels are notoriously aggressive, ESPECIALLY with an "intruder" of their own species.
Two more random announcements from me...
1) I got Jasper's tank done! Woot! Decided to go with the black gravel/red Flourite from the 18gal.
2) I'm glad I'm on glorified well water because I keep forgetting to add water conditioner to the tanks as I set them up!