Don't stuff them with newspaper, this is nonsense. They are synthetic, leave them in a warm well-ventilated place and they'll dry fast. It's going to be sunny this weekend so hang them on the line where sterilising UV can get to them. The cat pee smell comes from the cardboard liner under the insole and is the result of bacteria growing in the damp cardboard because you haven't taken the insoles out after wearing them. Leaving damp newspaper in them will just re-start the bacterial growth.