pick your day – a good hot day if you end up water washing them, means they will dry fast rather than gather a musty damp smell.
dry vacuum first, then try wiping overall with damp not wet cloth and or wet ones (baby wipes).

Vacuum to remove dust, sand and other particles trapped in the fabric. …
Pre-treat the stain by spraying undiluted distilled white vinegar over the affected area and wait at least 10 minutes. For stubborn stains, place a cloth soaked in vinegar over the spot. Scrub the cushions with a brush.
Fill a bucket with lukewarm water and add about half a cup of dishwashing liquid. …
Use a soft brush to give the cushions a good scrub on both sides.
Rinse and let air-dry completely in a sunny spot.

Some cushions have a removable cover, which is easy to pop in the washing machine

Theres brand called gone in 30 seconds or wet and forget from hardwares stores and it’s good

Good tips from Mom’s; will try some of them on my furniture too!

Jif and a scrubbing brush, then just washing up detergent and hot water, hose off and hang to dry.

I just cleaned mined

Pack them in a vehicle and take to a high pressure car wash, use car wash detergent on them, spray with normal stain remover (like sard) before taking them, this will wash them and get them really clean, drain them as much as possible, use large bin bags to protect the vehicle and take them home and let them dry outside, turning frequently.

Good question; thanks for asking as I would also like to know!