We generally advise you to remove old waxes if it contains any other product than Saphir and polish before conditioning the leather so the skin can really absorb all the oils. It is enough though to do this once a month. If you prefer a Mirror Shine on your shoes, you can leave the wax buildup on the toe area so it will be easier to bring this part of the shoe back to high shine. The vamp of the shoe, the area that flexes, should be cleaned properly though because it is important that leather stays hydrated here so it won’t crack over time.