Different methods depending on if using amps or vials of HCG...if vial, for example on a 5,000iu bottle I will cut it with 5ml of Bacteriostatic water, so every 1ml/cc is 1,000iu, making every tick (10) on a slin pin 100iu. So if shooting 500iu I'd go to the halfway mark and bam done. If using amps, score and open amp and using above calculation add about 2ml bact water into the amp, swirl gently, then draw the 2ml mixed solution and transfer to an empty vial. Then draw and add an additional 3ml plain bact water to the vial, yielding a total of 5ml/cc of mixed HCG with measurements the same as above. If you really want to get gangster with it, you can cut it with 2ml bact water total solution, giving you 5,000iu to 2ml/cc which yields 2,500iu per ml/cc and on a slin pin that'd be 250iu per tick (10). Hope this helps...along with the youtube vid big billy 86 referenced.