Don't know if you would consider this....BUT....while you are naturally clean, why not store some of your own urine in the freezer. It's good for a 1 - 1 1/2 years in air tight containers. When that right job comes along you won't have to fret about buying or finding a clean sample. I try to advocate freezing and using one's own clean urine for subbing after subbing with my own for 8 months for my PO.