Man I just flexed, bent, twisted, & folded the hell out of the soles with my hands and they were good to go by the second session. Just take out the insole and flex that shit in every direction. They’re defintely pretty stiff at first but it’s a small trade off for the durability. Idk something about microwaves is just iffy to me you never know how that’s gonna affect the various glues that keep the shoe together. It takes a lil extra effort to do it by hand but it’s not too bad and easier than trying to break them in on foot
Also, I’ve found that the flat footprint insoles are a perfect compliment to the Revlite midsole of the 533’s. Great balance of cushioning and boardfeel.