Hydrocarbon injection experiments have been performed to investigate the chemical sputtering yield of CFC at elevated temperatures (Tsurface 500K) and detached plasma conditions in the JET outer divertor. A plasma scenario in L-mode with the outer strike-point on the load bearing septum replacement plate was developed to detach the divertor and to provide the recombining target plasma. The operational window was explored in a set of discharges with strong deuterium puffng into the private-flux region. Langmuir probes showed a clear roll-over in the ion flux up to complete detachment at the target during the density ramp. Paschen recombination line analysis shows strong volume recombination with Te < 2:0eV prior to the appearance of an X-point Marfe. A strong reduction of the intrinsic CD photon flux was observed under these conditions in which local CD4 injection clearly led to CD photon flflux emission. This provides conclusive evidence for a reduction of the hydrocarbon flux and the chemical sputtering. Preprint of Paper to be submitted for publication in Proceedings of the 18th Plasma Surface Interactions in Controlled Fusion Devices Toledo, Spain ( 26th May 2008 - 30th May 2008)