Be careful when you do pasteurize them. I had a similar thing happen with a cran apple cider i just pasteurized last night, meant to do it on Saturday but got busy, and I had a few bottles explode. Its a bit scary after they start popping and your moving them in and out of the hot water. Only lost 3 but the ones that did explode, did so with a surprising amount of force for small bottles.
There's always the dishwasher method, load em up and run em through a cycle on hot wash. Results with that vary though depending on how hot your dishwasher gets but if there gonna explode that'd probably be the safest way. Maybe crank the heat up on the hot water heater first for best results.