Roger - I use oxyclean and cascade (unscented) on my better bottles. I’ve never really measured the amount, but I dump some in, fill it with warm/hot water and let it soak.
I’ve yet to encounter a crust that can withstand the soak.
Sometimes I will put an old sock on a bottle brush and give the interior a scrub, too.
I’ve never met any sort of brown crusty stuff that Mark’s Keg Washer and some PBW hasn’t been able to tackle.
Now, the 1 year old lambic crust in a 6 gallon glass carboy… that took about 40 minutes on the Keg Washer, but it still worked without me scrubbing. Pretty cool.
I’m going to clean a Berliner Weisse that sat for Five months - hot PBW solution to start, but it is a glass carboy, so no stress fracture worries, just regular fracture worries! I use my BB on short term fermenting beers that leave less of a mess. I also have a Dubbel in a plastic bucket that was looking highly crudded up and is ready for racking to secondary, so PBW will get a lot of use at my house this week.