On Sunday, we read in the Mishno that we may not use שעוה to light נרות שבת. The חכמי נרבונא, quoted both by the Tosofos and by the רא"ש, in fact, ruled according to the pashtuth of the Mishno, that in fact, we may not use wax candles for נרות שבת. However, the רא"ש was מלמד זכות on those who use wax using a strange argument that went something like this: "When the Mishno said that you couldn't ue wax, it only meant to forbid the use of wax by itself. However, if you mix wax with another substance, then it is fine. And of course, if wax mixed with another substance is fine, then surely wax used alone must be fine, too."
Would anyone please stand up and defend the argument of the רא"ש? And will anyone stand up and defend the Ashkenazzi practice of using wax for נרות שבת?