Have you broken any of these clods up to see if they are formed around rocks?
If they are just compacted soil, they
should not remain clods once dug up unless there is clay in there.
(on our
land we have very nice topsoil for about a foot in most areas, but when I go digging deeper I can get clods that look like the top soil but upon splitting they show their red clay cores).
Either way you have many choices; you could use them in your
compost heaps as a layer, you could use them in the brush piles as you have mentioned, you could mix them in with finished compost,
you could use them for path way borders ( rains will most likely melt these which would allow them to spread out and reincorporate into the path and outer edge of the path.
If they do have a clay core, you can harvest the clay for pottery use or
cob making.
We have one area that I have reserved for clay harvesting since the red clay is great for terra cotta items. One of the projects on my list is a clay bread/ pizza
oven.
You also can use clay for
pond lining, it will seal a
pond bottom very nicely if you spread the clay then lay on some grass seed, let it sprout then fill the pond, the resulting gley will seal that pond bottom.