Is submerging bottles in boiling water (assuming they've been rinsed out) for a few minutes a good method of sterilization? I'm still planning on spraying some metabisulphite afterwards, and then some star-san just before bottling. I just want to know if I can substitute a bleach soak with boiling water water. This is because I find the bleach method takes forever, including having to remove the flip-top wiring from the bottle, and rinsing the bleach-solution residue from the bottle.
It should work fine for sanitation, as long as the bottles have been cleaned in advance. If you were planning on using some star-san later though, why bother with the boiling water (or even the bleach in previous runs)? There really is no reason to sanitize twice like that. Clean the bottles well and let them sit until ready to use. Before bottling dunk them in some star san. No need for wasting time with boiling water or super hot bottles.
Simply washing with dish soap to remove residual beer and dirt from outside (lipstick) is fine. I then rinse with sani solution before storing. When I am ready to use a bottle, I rinse again with sani solution and bottle. No boiling water and hot bottles. No bleach. I have tossed a couple bottles that got some stuff growing in them because they were not washed, but other than that no issue.
Same with growlers.
Just a note of caution.
Bottles are not tempered glass. Dropping cool bottles in boiling water may break them or make micro fractures that will fail under carbonation pressure. Always do temperature changes slowly, submerge bottles and then apply heat once at 180°-200°F remove from heat. Boiling can make too much movement and bang bottles around.
I find an easy way is chemical wash and rinse and drip dry, put lose foil over each then place them in a cool oven and let them warm up to 200°F-250°F for a few minutes then allow them to cool with oven closed. Then pinch the foil tight, they are now sterile and are ready for bottling. This is a good method if you want to prep a lot of bottles that won't be filled for a couple of days.
Nothing wrong with most suggestions here, but my typical method was clean with B-Brite (Oxyclean also works - look for cleaners with sodium percarbonate) after drinking and then storing and then sanitizing just before filling. Sanitizing can be how you wish, boiling with care is okay, but you don't need multiple sanitary treatments. Make sure you're clean as can be (no visible grime/dirt/glue/compounds) and then sanitation takes care of the rest. I've also heard of homebrewers baking clean bottles in the oven at low-ish temperatures.
I think this method works especially well for turning commercial bottles into homebrew bottles.