It may still come out over time. Also, you can try looking online for a cleaner specially designed for that. I have cats too and have been using a hard...
Try toothpaste, which works really well for soot and scorch marks. Put a thin coat of toothpaste across the scorch, leave for 10 - 20 minutes, then clean off with...
No. The best prevention is avoiding things that allow the bacteria to grow, such as unsafe sex practices, douching, overcleansing, irritating detergents used for clothing, scented feminine care products, etc.