Last year, I went to great lengths to mix up a copper sulfate solution, and it
pretty much did the trick. But this year, I got a faint whiff of H2S in a
couple of batches, and instead of using CuSO4, I took some copper sheets (the
kind that they sell in craft shops), cut them up into thin strips, and swooshed
them inside my carboy. I "think" I achieved the same results.

Lee