well ive done it... after using gt1009's method, i got the water in the bucket stirring from brown to slightly clear/ milky-ish in about an hour of constant flushing.
i used a 7 inch long, 2.5 inch wide cup to scoop about 6 cups of sand into my 30 gal and upon finishing i thought it was a job well done... until my hands dried.
my hands were sticky as if it was salt water!!!!! OMFG... i thought i got rid of all the salt, i smelled it and tasted it before i put it in and it wasnt salty but why is it sticky!! its sticking to my arm! was there still salt in ther?!?! now my fish are swimming in it and the O'opus doing its thing but now my 4plecos, 2 africans,and red devil are absolutely fresh fish... how do i neutralize it quick!?? all fish are acting fine but with fish you never know! aRRRG!!
UPDATE! yes! all my fish are fine! i borrowed a D.O. meter and Hydrometer from my professor and the salinity reading is ZERO!!! YAAAAAAAAAAAY!!! i must be a good rinser ^.^