I assume you mean that you want to make a BBQ sauce to use fresh sometime during the next few days? You do know that there likely is no way to take a brine leftover from a pickling recipe and safely convert it to any sort of canning recipe, don't you? All canning recipes, in order to be safe, must follow safety-approved recipes developed with a specific density and pH in mind and must be followed exactly (although some allow a certain amount of alteration, which is clearly detailed in the recipe if such an alteration is allowed). When I have brine left over, I refrigerate and use it to pickle something else (usually more peppers if I am making candied jalapenos) or pickles (if I have cucumbers at the right size/stage) within the next day or two.

It could be one of the canning experts over there at the Harvest Forum will have a better answer for you because they know what they are doing and what can and cannot be done or changed or modified. I follow canning recipes strictly and don't free-lance and change things because I am not a canning expert and I don't want to make any changes that make a home-canned product unsafe for human consumption.

Most recipes for BBQ sauce for canning start with a tomato base, but you might be able to find some sort of vinegar-based recipe (isn't North Carolina style BBQ sauce more of a vinegary one than a tomatoey one?). Just be sure that, if canning, it is a recipe developed, tested and approved for canning.

I see all kinds of made-up recipes for canned food on the internet that I'd never make and never can and never eat because they are just some random person's recipe and never have been tested for safety. I don't care if they have made/canned that recipe a hundred times---if it has not been safety tested in a food lab and safety-approved, then canning/eating that food is like playing Russian roulette. Safety testing is imperative because botulism-contaminated food often is deadly and the food doesn't look spoiled, ruined, moldy, etc. It can look, smell and taste just fine but be deadly when eaten. Sometimes people get really offended when told they cannot safely can their great-grandmother's recipe of some type because it does not meet current guidelines, but times have changed and we know more about safety now than we did then, so it always is wise to adhere to the most current canning recipes and guidelines. I have canning books that date back at least to the 1980s and possibly the 1970s, but I don't use a recipe from them unless is it included in the current, more up-to-date canning guides as well.

If Digdirt, Linda or any of the other experts over there (there are quite a few of them, and some are Master Food Preservers, while others work in the field of food preservation or are certified canning instructors) have a solution for you, I hope you'll tell us about it.