Try not to use dish soap It may hurt your finish. In fact in some cases Like Mercedes Benz they tell you in the owners manual to never use dish soap under any circumstances. What you should use is an automotive grade wash system that will strip your old wax off .Waxing on top of wax is not a good idea unless you do it soon after the first layer for a layering effect. I use P21S total car wash before use the paint cleanser and then I wax . I use P21S shampoo to maintain betweeen waxing. P21S Total wash is German made and is used and recommended by Mercedes Benz BMW Rolls Royce McLaren and Honda Europe .In fact The NSX and The S2000 come from some dealers overseas with a P21S car care package.
P21S in my opinion is far better than Maguiar's and is not expensive if you know where to buy it. Try www.aandmmotorsport.com they carry P21S as well as a number of other brands. If you have questions about car care they have techs answering e-mails and phones that are Honda enthuesiests. Let me be clear I am not related to A and M I just like great service and good prices. They have a complete Honda performance line also.