Re: cleaning compound for inflatable tubes
+1 on the soft scrub. If that's not enough, and the tubes are really cruddy and surface etched from overexposure to UV rays and the elements, try a stronger cleanser that contains bleach. Wet a test patch, give a liberal shake of cleanser, work it in a bit, and let it rest, wet, for a few minutes. Then, scrub very lightly and rinse off. The trick is to not do further damage with strong abrasives. After any treatments, finish off with 303 Protectant to help protect the fabric.
Larry