That thing about being anti-bacterial is true. By simply being a barrier that microbes (and dirt, and water) can’t penetrate. For short term wound treatment, petroleum jelly is an excellent barrier for an open wound that’s not bleeding. Bandages inundated with it can keep a wound clean in the roughest conditions.
dd if=/dev/zero of=/dev/sdX bs=1M
This command is much faster. Instead of random bits, it just marks everything zero (dude). Is good enough.