WTF!!!Liiiiar, I was the one who did it to zanji.
You don't even understand the seal xD
It isnt "full of bad chakra that you have to replace", it works by forcibly drawing out chakra. The way you fix it, is by giving you control over how much you draw out and when, so you can use it with your own will, like how naruto uses the kyuubi chakra.
I changed it!!!!!
>_<
I removed the chakra out of curse mark and filled it in so that it wouldnt absorb random chakra. And how would you konw how to do eals.>_<