Complex sentence: The 1864 law which had substituted bronze for copper nickel had also outlawed the "copperheads" or private token issues; even though these could now only be issued anonymously, and so could not be redeemed, the copperheads were preferred to the 3-cent shinplasters.
Split into simpler sentences: The 1864 law which had substituted bronze for copper nickel had also outlawed "copperheads" or private token issues. Even though these could now only be issued anonymously, and so could not be redeemed, the copperheads were preferred to the 3-cent shinplasters.