I'll admit I've never heard of these embrittlement claims as well.

Me: I soak the chain overnight, or at least for a couple of hours, in mineral spirits in a coffee can. Pull it out, scrub it, rinse, then wipe down clean. Hang on a nail in my basement overnight. Spray it down with brakecleen, wipe again. Put a drop of chain'l on each roller (laid out on newspaper), then let sit overnight. Wipe down in the morning, and install.