Basically: no. The construction of the Model M disallows removing the backplate after the assembly is removed from the case. On the Model F, however, the backplate is not attached with plastic rivets, and had no rubber membrane that could trap liquids, so after the electronics were removed, it is feasible to wash it in a dishwasher. Inadvisable to say the least, if you want your PCB to remain non-warped.