Yes, when i used to clean my chain with soapy water, it did have a film of rust on it the next day, more or less. Found that oiling the chain after the wash would stop this. It was a SRAM951 chain, and the plates seemed to rust very easily. Now i wash my chain in methelated spirits; am still not sure if this is right, but its been ok so far, then i wait for the spirit to dissolve, go dry, and then oil it.