How to remove ALSA mixer entries?

I'm trying to make I2S on a Raspberry Pi, and I had to edit ALSA config files (/etc/asound.conf and ~/.asoundrc) a lot. Now, because of the changes I did to the config files, I now have to entries for my I2S chip in the alsamixer. These are called "PCM" and "SoftMaster", however I guess the names don't matter here. But now that I undid these config changes, the mixer entries are still there and I don't know how to remove them. The files ~/.asoundrc, /etc/asound.conf and /etc/asound.conf.old are all empty, but somehow Alsa still finds two devices called "PCM" and "SoftMaster". So how do I remove those devices or "reload" the alsamixer?