That 'screw' has no glass in it on the Air
It's literally just a ring to cover the filter threads. Also some if not all of the Mavic Air lens is plastic, so you need to be careful not to etch it (I am not 100% sure what the front element is made out of - it might be glass).
Never use harsh cleaners like Windex on milticoated optics - ammonia and other additives they use can damage lens/filter coatings, damage plastic, and they also do a crappy job of cleaning because it's not 100% residue free.
First, blow/lightly brush off any hard particles - those will scratch the lens when you rub it. ESPECIALLY if it's sand.
Amazon.com : Giottos AA1900 Rocket Air Blaster Large - Black : Camera Cleaning Kits : Gateway
If it's a finger print or similar smudge, use a Lens Pen Mini (Mini size is best for the Air) - they use a dry carbon compound that leaves zero residue and they have a brush on the other end for debris:
Amazon.com : Lenspen Mini Pro II Compact Lens Pen Cleaning System : Camera Cleaning Kits : Gateway
If it's more stubborn, use something like a Zeiss pre-moistened lens cleaning pad (you can buy a huge box of them at WalMart in the USA for $5.00). Great for glasses/sunglasses too.
Zeiss Lens Wipes 100ct - Walmart.com
If it's really stubborn, you can use something like ROR (Residual Oil Remover) which is safe for even the most expensive optics:
RORResidual Oil Remover (2.0 oz)
These are best practices for all lenses, not just on drones