Are these in your hang on back / HOB filters?
You continue to keep the BB colony going in them by rinsing the filter pad (or swish gently) in either pwc water, the cleaner part of the water , or treated water to preserve the BB.
Keep until they are beginning to wear through, and add a new one behind and and allow it to get a good colony going for about a month to 8 weeks and then you could discard the falling apart one. I have had filter pads last well over a year, though I haven't specifically used this brand.
Or if there is already a BB colony in another part of the filter/aquarium and these are simply for cleaning the water then when the flow seems to be reduced by mucky stuff.