Pick off any leaves or moss and trim the ends of the stems. If necessary, wash them very briefly – it’s a pity, but they are spoiled if they have grit in them. Hold them under the tap in a colander, turn them over a few times – any with persistent dirt may need individual washing, but make it as brief as possible. Drain them first in a colander and then on kitchen paper, place more folded kitchen paper on top and and gently pat them dry.
Another method, told me by the market lady in Narbonne Halles, is quicker. Bring a pan of water to a boil, drop in the chanterelles, boil for 1 minute, drain in a colander, then spin them gently in the salad spinner.