i am amazed at the sheer level of unhelpful idiocy in this thread.
he did not ask whether people agree with his needle practices, he asked if anybody knew a way to sharpen needles. dead set there are like 20 posts in this poor guys thread without a single one actually addressing the aim of this thread.
what you should do, is start your post with detailed advice on why re-using sharps is bad practice, so as to keep in the harm reduction attitude of this board. after this disclaimer however, people should actually address the dudes fucking question. because it is quite obvious that he does not care for a dozen fools repeatedly saying not to re-use. he knows this. as it stands, he shouldnt have bothered with the thread in the first place, because its saying nothing he doesnt already know and nobody seems to have even digested his actual question.
so, i will give it a shot.
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Firstly mate, you should never re-use needles. its good that you clean them, however nothing will ever come remotely close to actually using a fresh spike.
is there a way that you could not inject until Wednesday? you could snort, or plug your drugs? also, on wednesday, and in all future visits to the exchange, try to make sure you'll have enough fresh spikes. having more then u need is a lot better then having less. remember that.
However, if you really really must, then you could try a piece of steel wool or something? theres not many options for such a delicate instrument. also try and minimise the number of shots your doing, as each time it pierces your skin its getting blunter. and if u MUST do this, then make sure u keep disinfecting the spikes after every use.
stay safe bro