The process of converting “as-synthesized” zeolites which contain organic templating agents generally begins by calcining the material to remove the organic material. Most often, this initial calcining step is performed in the presence of O 2 which is thought to help burn out residue which forms during the thermal breakdown of the organic template. We have discovered that O 2 promotes the formation of residue from tetraethylammonium ions in zeolite beta (BEA), probably by participating directly in a polymerization process. This discovery has also been extended to tetrapropylammonium ions in MFI and to simple amine adsorbates such as 1-propanamine adsorbed on acid sites in both BEA and MFI. We therefore believe that this is a general rule which may be applied to all amine templates in zeolites.A more efficient route to organic template removal is to first calcine the material in the absence of O 2 so that the polymerization process which involves O 2 is suppressed. This results in a material which has only a trace of residue which can be removed by heating briefly in O 2 at a moderate temperature. Materials initially calcined in O 2 require either a lengthy treatment at a moderate temperature or a shorter treatment at a higher temperature to completely remove the residue.