It's not practical because the amount of time required for the UV light to scramble everything would be too long or the power of the UV light required for a sma

It's not practical because the amount of time required for the UV light to scramble everything would be too long or the power of the UV light required for a small amount of time would be too dangerous. It's also hard to ensure light gets into all the places it needs to get into, soap and water does a much better job.