If there is a LOT of dust and debris I hit it first with the veggie sprayer in the kitchen sink. Then clean with cleaning fluid and dabbing with cloth. Rubbing is what scratches it. Get the dust off first!
I have one of the full cleaning kits, mine happens to be a vortex kit. It includes a brush to get the big stuff, cleaning solution, a wet rag, and a microfiber dry cloth to buff it out. Worthwhile investment of 20 bucks to keep my lenses scratch free.
I always have my microfiber cloth and lens pen in my harness or in my pack if Im not harnessed up.
At home I use a bigger cloth but still use the lens pen. I use the glass cleaner I get from my eyeglass maker if I need
thing to clean the lens. I have a lot invested in my scopes and binos and I try to take good care of them. Im pretty careful what I touch those lens with.