In the onUse/onEquip/whatever, add
%obj.hidenode($rhand0);
%obj.hidenode($rhand1);
and onUnequip or whatever:
%obj.client.applybodyparts();
%obj.client.applybodycolors();
I think...I'm not quite sure what the exact functions are for onUse or onUnUse (I don't think they specifically exist, but they probably have some other function that would work).