Field strip is when you fall in the muddy creek 15 miles from the truck.
Grip comes off, mainspring comes out, cylinder and crane come out, hammer comes out and so does the trigger assembly.(The order's a bit off, but basically it comes all the way apart.)
On a ruger, if you can get the screw out of the grip panel, you're home free.
Then you wipe down everything real good, put the thing back together. Now it at least functions the rest of the day/way back to the truck.
When hunting with a rifle, using a pistol as backup, this is not a major concern. But when hunting black bear with pistol only, that walk from the bait station to the truck at dusk and dawn with a non-functional pistol would be very hair raising.