To help oxidation, stick some saran wrap over the top of the funnel, every little bit will help. I have used heat, not used heat, used acetone, used methanol. The one thing i noticed, the browner or redder the tren (which comes form oxidation) which came from using heat, the less potent it seemed. This last batch I used acetone to extract, and was anal about letting the least amount of air interact with my oil/tren, and I have had some of the most potent Tren ever. Before I had to use 1 ml ed of supposedly 100mg/ml tren, Im now using 1/2 a ml of this 100mg/ml tren, with the same affect.