Domestic Cat Repellents

Does anyone have stories to share on how to repel domestic cats from lawns and gardens?

My cat -- and several other neighborhood cats -- have taken to using my neighbor's yard as their personal box. My neighbor has no animals and doesn't intend to get any. Since we live next door, he's automatically put all the blame on my cat. Since the first incident was reported this summer, I have made some effort to circumvent the action from my cat (e.g., won't let him outside until he first uses the litterbox inside). I have checked in with the neighbor several times to make sure things had improved -- and he said they had. However, last night the neighbor came over to say the problem has increased.

...while I'll accept the blame for his piles and pay for remedy to keep my cat out of his yard, I certainly won't accept the blame for everyone's cat! Heck, we're even cleaning up mess from other neighbors' cats from our front yard. I feel a bit weird since I can pretty much ID our cat's mess -- he's got known intestinal problems and always has runny stool so I know which piles aren't his. Of course, I haven't pointed that out to the neighbor as I don't want him to think I'm nuts in being able to identify cat stool or think that I'm trying to pass the buck to other neighbors. I just am a believer in fairness and personal responsibility...and I'm doing what I can to be a good neighbor but not drive my cat nuts by confining him to the house 100% of the time. My cat only goes outdoors for a few hours each day...and sometimes only 30-60 minutes a day. Anyway, I've digressed...

The research I've done include the following. Have you had good/bad experience with any of these?

• Shake-Away Powder - granules with fox and coyote urine smell to scare away cats
• De-Fence Dog and Cat Repellent - granules
• Shot-Gun Dog & Cat Repellent - granules
• Liquid Fence Dog & Cat Repellent - liquid
• Boundary - liquid
• Cat Stop - ultrasonic repellent device
• ScareCrow - motion-detector controlled water sprinkler
• Moth balls
• Pepper (black, cayenne, other; have heard it only lasts ~3-4 days until reapplication is needed)

...any others?

Need something that works well, won't hurt the neighbor's grass, but will deter my and others' cats from his yard.

Thanks, in advance...

:-T