I take an old container of Labrada Protein and recap the syringes and use the container as a safe sharps container. When it gets full, I throw it away.
I wrap em up in a napkin, then stuff them into an empty sports drink bottle (colored bottle so you cant see in it) then i toss them in the dumpster of the local GNC. I figure that way its pretty safe nobody will find them or accidentaly poke themselves.
-D2