There's been some debate... I think Ichibans video's are 90% Satire with 10% enough real data to cause problems for people that don't know what the heck they are doing.
Simple green is supposedly safe for use with aluminum "When used with caution and according to the instructions," from their web site directly, but carbs are not aluminum. Usually they are some mix of pot metal, brass, etc etc etc... and as such when you mix different types of metal in a alkaline aqueous solution you can get some property shifts. What this means is if you have a piece of steel mixed with some kind of pot metal, the pot can turn or stain black (or at least a darker finish) if you leave it soaking too long. That being said, if you are just doing a dip in some simple green for 5 to 10 minutes in a hot US liquid bath and then rinsing it off with some clean water and then drying it off you'll probably be fine. According to their web site it was developed for use in the airplane industry specifically so who knows really....
CLR, definitely bad, that is light acid, essentially, can affect the bore on your throttle shaft and other places.
I trust in pine-sol, it has never done me wrong, the only thing I do a little different is heat it and it is extremely effective at not only cleaning carbs but cutting through a ton of greasy parts, but then again, I use a hot plate in the garage, so even if i do hit a flash point, I just kick it in driveway until it flames out.