Ok I'm going to be the first to admit that I totally gave away my last pair of Nikes because I literally could not for the life of me get the smell out of them!
When it's just a spot!
Go for a Magic Eraser and you'll get spotless shoes in no time. Just scrub over any stains or scuffs and they'll look brand new! Baby wipes and cleaning wipes will get rid of spots super fast and you've probably already got some hiding in your bathroom already. One of my favourites are Tide To-Go Pens - I stock these everywhere, in the office, at home, in my tote, they're fantastic!
When it's more than a spot
Are your shoes in desperate need of a clean? Go for dishwasher soap, water and a toothbrush to scrub away at dirt and grime. Make sure you rinse everything off completely and leave them to air dry. White vinegar is also an incredibly good cleaning tool - again use a toothbrush dipped in white vinegar or use a paper towel to give your shoes an overall clean.
When they're giving off a bit of a smell...
Alright, everybody sweats. But sometimes that odour gets into our shoes and somehow stays there and nobody wants that. If you're in a pinch, seal your shoes in a resealable bag and put them in the freezer overnight - I have no idea how this works but it does! Go for essentials oils and drop lavender, tea tree or peppermint oils into each shoe to reduce the smell.