CV, I've done it w/ hot water as the honorable Rick says. It will sometimes leave a cloudy finish on the scales that polishes back to normal. Some of the better guys in resto advocate steam over water - haven't tried yet.
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Should you find the scales bow inwards - closing up the gap that the blade needs to occupy, a popcicle stick or similar can be inserted between scales to prevent this. If the gap is normally too thin to accept the popcicle stick, sanding some thickness from the stick should give a proper fit. The stick holds the gap at the right width while you apply bending pressure to the softened scales.