Methods have been assessed for the analysis of thick layers of redeposited material such as may occur in ITER, using a film -100µm thick from JET as a test sample. Neutron-induced Elastic Recoil Detection (n-ERDA) was found to be particularly useful. A comparison of the retention of D was made between the graphite and Be divertor tiles used in different phases of the 1994–1995 JET operations. The redeposited films were a mixture of C and Be in each case due to incorporation of material eroded from the main chamber. The overall rate of retention in the divertor was similar whichever tiles were used, and it was found that layers saturated with D were formed on cooled areas of tiles shadowed from the plasma. If surfaces are held at higher temperature (e.g. 300°C or above) the retained D concentration is an order of magnitude less. Diffusion effects were observed into the Be tiles which require further analysis.