An interesting thread.
To summarize my understanding: many (most) shoot .38 Specials in .357 Magnum cylinders; clean the .38 Special "carbon" residue from the cylinder; and shoot .357s with no ejection problems.
I'd always adhered to "shooting .38s in .357 cylinders will etch (flame cut) the chambers over time and make ejecting .357 cases difficult, if not impossible" consensus from the early 1970s.
So a trip to the range was in order to run an informal test.
After closely inspected the six chambers in a Model 66 (all clean and shiny), for the first time I fired .38 Specials in .357 Magnum chambers (100 rounds).
Returning home, I thoroughly cleaned the 66 and re-inspected the chambers noting a faint ring in each where the .38 residue had been (re-cleaned the chambers noting no change).
A question: Does anyone who shoots lots of .38s in their .357 have trouble with ejecting factory or full load .357 Magnum cases?
A request: Please post pictures of your cylinder's chambers.