I can't say anything about dilution because I've never tried it. However, substitution in most situations is still a sure thing. Be sure that the product you purchase is stored properly and mixed exactly as the instructions say (if synthetic). If you're using a real sample, make sure its refridgerated or frozen (depending on how long you're storing it). Personally, my boyfriend and I have been sharing a Pissinator, which comes with a synthetic sample but you can fill it with a real one if you can find a clean donor. Check out the Pissinator update thread and use your own judgement. :jointsmile: