@ch3apshad3s I regularly get smelly hand-me-down and here is my process:
1. (Too late for this now, but keep in mind for future) don’t wash with our normal clothes
2. Just run in rinse and spin once or twice through the wash (this should help get out excess soap/detergent embedded in the clothes).
3. When washing with your preferred detergent, add vinegar to fabric softener cup
4. I personally would avoid the dryer and air dry (especially if you can get them in the sun) until they are less stinky.
It does take a while though. I swear some of my kids clothes still have a scent after the first few washes, but it fades. I hate it so, you know, solidarity.