Most of the "compost activators" I have looked at smell like a bad chemical factory and list very high levels of Nitrogen in the ingrediants. I have not had to use any of them in 50 plus years of composting, even back in the early days when I was just learning. If the mix is close to right, 3 parts vegetative waste to 1 part of a nitrogen source, with just enough moisture the material will get digested by the bacteria that is ever present ready and willing to get to work digesting it when conditions are right.
The only reason they might not would be if the material was sprayed with some poison beforehand.

Isn't it strange how folks will pick up a minor point of a posting, but ignore the main point.
My point was to use finished compost as a brown cover, if you want to get fast acting compost.
Oh well, soldier on!

Beeman, I accidentally learned the same thing just a few years ago!

I had a bunch of parings, peeling, skins, etc from fruit/veg processing (home), too much to just dump into the composters without trouble (stink), and no browns.

I had just sifted a batch of finished compost into a garbage can to protect it from coming rains, and it was all I could think of to use. Oh, well, thinks I, it will just delay finishing it (again), and maybe add some more good stuff. Then I tossed an old tarp over it because I didn't want to get it soaked by the rain.

WOW! Just what you said! There must have been enough live microbes in the compost that they jumped right to multiplying and chowing down. Although I did have about 1.5 cups of brown sugar that ants got into, so I sprinkled that over the top for good measure (and to get them out of the house).

I usually add a shovelful or two of soil to a building compost pile, but it seems to work faster if I add compost.

Gardening... always a learning experience!

Sue

Ya, I stopped cleaning the tumblers out completely when I empty them. Leaving a few pail fulls of 'post and mixing it up with the new material made it almost explosive. Doesn't seem to reduce the total time at high temperatures but it got the temp up there in less than a day.

Lloyd