Pressure washer is your best best.
thought so thanks
What type of stains? IF it's from mortar, you can clean with muratic acid but you will need to be careful and wear protective clothing.
If you use a pressure washer and these are brick that are lain, be careful not to disturb the mortar as it can remove it.
I think it will depend on the stain but here is a post that might help. https://www.thespruce.com/how-to-clean-brick-patio-walls-2736987