It's really simple and I have used it for years.

Dogs crap at places where other dogs have either peed or crapped.

Anyway, you get a spay bottle and fill it with vinegar.....

The only snag is when the crap is on grass, but then you carefully give the area separate light squirts so that if you kill the grass it recovers very quickly.

It can last for years, even if there's a tree or fire hydrant involved, because once there's no dog stink from other dogs, then all dogs stay away.

It's quite entertaining to watch the first dog as it has always been in the habit of either crapping or peeing without fail at the location, and it will try to get to the doggy stink but instead, even when a foot or more away from the actual sprayed point, it will reject the place, then immediately swing it's head back to see if it missed it, but once it finds only the vinegar smell it moves on.

You can even spray directly upon a previous dumping of crap and the other dogs reject it as stimulation.