Best way to remove these stains??

Dare we ask what caused them?! Looks dodgy as!

Depending on what 'substances' the stains are, there may be a different method to remove them, might be worth asking in the detailing section as well.

 

I would have thought a wet vac would get them out.

Looks like some extreme dogging gone wrong there...

 

Spray extraction machine or wet vac as it's known should do it.

Depending on what it is of course.

 

I genuinely got toothpaste on mine, looked real suspect i used a wet vac and came our a treat