Methods and apparatus for remote plasma processing are provided. In various embodiments, a reaction chamber is conditioned by forming a low recombination material coating on interior chamber surfaces. The low recombination material helps minimize the degree of radical recombination that occurs within the reaction chamber when the reaction chamber is used to process substrates. During processing on substrates, the low recombination material may become covered by relatively higher recombination material (e.g., as a byproduct of the substrate processing), which results in a decrease in the amount of radicals available to process the substrate over time. The low recombination material coating may be reconditioned through exposure to an oxidizing plasma, which acts to reform the low recombination material coating. The reconditioning process may occur periodically as additional processing occurs on substrates.