I don't buy the "starter"/"activator" if that's what you are asking. I do occasionally buy different brand bagged compost -- usually when they look newly delivered and not last year's inventory nor like they had been sitting in the sun and rain -- and put some of that in my compost piles and some in the AACT (actively aerated compost tea). I put in the strained dregs from the AACT in the compost piles. I put in old juice, yogurt and soured milk, lacto-fermented pickles that got too old or the juice, moldy bread and old rice. Bokashi and Bokashi leachate when I have some.
I put in seashells and seafood scraps including lobster, shrimp, and crab shells.
Except for the tumbling composters which I just retrieved from my parents, my compost piles are on the ground and become earthworm haven once they cool down.
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