A strong light emission of the C2 Swan band and the CD Gerö band has been observed during strike point sweeps in the corner region of the inner MKII SRP divertor of JET. The light emission could be correlated to the decomposition of a probably soft hydrocarbon layers at the corner entrance. The ratio of the C2 and CD photon flux indicates a preferred emission of C2 and thus of C2Hy particles. The layer has been removed within one H-mode discharge, where the strike point wasxed at the corner. In the consecutive discharges no enhanced light emission from C2 and CD could be observed and the C2/CD ratio drops signicantly. The spectroscopic observations are in line with measurements on the quartz microbalance located near the louvre. A similar layer could not be identified in the lines of sight of the spectroscopic systems in the outer divertor.