I tried to change the Alloy recipe for Osgloglas by removing the existing one and adding a new one with the following code in a crafttweaker script:
mods.tconstruct.Alloy.removeRecipe(<liquid:osgloglas>, [<liquid:osmium>,<liquid:refinedobsidian>,<liquid:refinedglowstone>]); mods.tconstruct.Alloy.addRecipe(<liquid:osgloglas>, [<liquid:osmiridium>,<liquid:refinedglowstone>,<liquid:refinedobsidian>]);
The new recipe was successfully added, but the old one was not removed.