Personally if I was you I would paint one of those barrels black and drill holes into it ,about 20-50 holes all over/around the barrel,place your clippings,grass,scraps etc.water and let stand out in the sun.Every time you add something water it down and keep doing that for about 6 months to a year and you should have good to okay compost.We tried this way at my kids school and the black one made it the quickest.Also if you have a lid for your barrels you can use one of them as a compost spreader by drilling holes in the sides (alot of holes about 100 or more).Put the finished compost in the barrel ,put the lid on and then roll it over the yard.plus it;s a work-out!!.