They work for me. I have v1.96.
removeAllWeapons this in a units init field, or
removeAllWeapons unitname in a script work fine.
I have never used
unit removeMagazine weaponName
because I have never needed to remove only one magazine
but I have used
unit removeMagazines weaponName
to remove all the pipebombs from a Black Op
this removeMagazines "pipebomb"
and that works as well.
Are you getting any error messages?