1) Dump it on top of stubborn weeds. It should kill them -- and then leave behind enriched soil. This may work especially well on weeds that prefer alkaline soil, which means most of what's native to the western states. Gee, I wonder if it would kill stump sprouts. Maybe not all at once, but the system produces a steady supply of leachate and pre-compost so you could just keep going for a while and see what happens. This is doubtless much less toxic than chemical herbicides.
2) If you have alkaline soil to begin with, the high acidity is an asset, not a problem. Here is a reference to soil pH and a map of average pH by state for America. The western states run alkaline, making them ideal for this method. You probably don't want to put more acid into eastern soil. Midwest is moderate.
I got to exploring what weeds I have here at Fieldhaven and what that means for the soil.
Dandelion, moss, common mullein, plantain, wild strawberries -- acidic soil.
Burdock, chickweed, chicory, dandelion, lamb's quarters, pigweed, pokeweed, purslane, Queen Anne's lace -- fertile soil.
Chicory, dandelion, milkweed, plantain, thistle -- heavy clay soil.
Foxtail, goldenrods, moss, sedges -- wet soil.
Chickweed, dandelion, lamb's quarter, plantain, purslane, ragweed, rough pigweed -- previously cultivated soil.
Here we have thick black glacial till. While high in organic matter, the base is more clay than sand, so it runs heavy. That means it doesn't drain very well, and right here is reclaimed swampland. Sort of. Nature disputes that claim several times a year. So we have parts of the yard that get soggy, and that's where those dampland plants show up. The prairie garden has a lot of sedges but is mostly goldenrods. All around us is farmland, and parts of the yard have been used for gardening before.
Some other indications ...
* Burdock grows in soils very high in iron and sulfate, and very low levels of calcium and manganese.
* Buckhorn Plantain indicate very low levels of calcium, low humus levels, and very high in chlorine, magnesium, potassium, and sodium.
* Common Chickweed and Mouse Ear Chickweed indicate very low calcium and phosphorus levels, and very high potassium and sodium levels.
* Dandelions indicate very low levels of calcium, and very high levels of chlorine and potassium.
* Red Clover indicates an excess of potassium.
* White Clover indicates very high levels in chlorine, magnesium, and sodium.
I know we have high iron because it was in the water back when we had wells.