The passenger sideview mirror on the Sienna became so discolored and stained, it was useless. I purchased a replacement mirror glass from Bezos for $15 or so thinking the problem was the mirror itself. So I removed the mirror from the housing and put it on the bench. Since it was already FUBAR, I had little to lose.
I used a heat gun to pry things apart and the discoloration improved and moved a bit. This is a fancy auto-dimming, heated mirror with integral turn signal. As it turns out, there is a coverglass over the mirror with some electrochromic gel sandwiched between the two. Sometime last Winte, the seal became compromised and the gel turned dark brown.
I cleaned both surfaces with solvent and was able to restore almost all of the original reflectivity. That goop gave up quite a fight, but ultimately, most goop surrenders to lacquer thinner. Snapped things back together, plugged in the connectors and everything works except the auto-dimming. I'm ok with that. I spent a minimal amount of time trying to find the correct assembly online, but the van is 18 years old, so I'm not too worried. It's used primarily for trips to Menard's, Orange Hell (Thank you Kay for that apt name), landscape suppliers and lumber yards. None of my other work trucks had something so fancy, so I'll live. Now the heated seats; however, those are IMPORTANT.
Sorry. No "after" pictures.