Opinions - should swim be scared

[frankz81]

swim is wanting to try heroin but is a little bit chicken due to the fact he has read brick dust and glass particles can be found in it...
swim would try a teeny weeny dose to begin with but its all the impurities that scares him... could something besides od'ing by having too much kill him?
swim has heard quinine is used to cut it, but swim is fine with quinine as his doc prescibed it to help with cramping legs from wd.
what other impurities could be fatal even if it is properly filtered?
obviously swim will try and use the most credible source possible, but even then swim cant be sure of its history...
should swim look or smell for anything out of sorts?
i dont know what forms of h exist where i am, but i am pretty sure i wouldnt come across the mexican black tar variety