The only point in using these two compounds together, in my opinion, is to preserve muscle mass while cutting fat. The thing is that clenbuterol is non-selectively catabolic, so it will also reduce your lean mass, not only fat. Meanwhile, anavar will help preserve your lean mass, and will also contribute to fat loss. However, this is by far not the optimal approach to cutting, and you should use some safer compounds that were at least meant for this purpose. For instance, cardarine GW was designed for fat loss and muscle maintenance, so you would be getting both effects with just one compound. However, you will neither have the side effects associated to clenbuterol use (mostly stim related side effects), nor will you get your testosterone production suppressed. Besides, Cardarine will drastically increase endurance and improve recovery times, which will contribute to better cardio, and even more enhanced fat loss.