RC papers shouldn't be left wet for too long. But from what I've observed, the maximum wet times quoted by the manufacturers are VERY conservative. Often, they'll quote a maximum wet time, from developer to wash, of under 10 minutes. I've had them sitting in water for upwards of two hours in some cases, and there were no adverse effects that I could see from that treatment. Some of the prints are pretty old now, and they're still fine. I have in-advertantly left RC prints in a tray of water overnight. These did suffer from some warping, so there is something to the maximum wet time story. Fiber based papers seem to be almost completely insensitive to wet time. An overnight soak in clean water will certainly do no harm.