Here are a few ideas to add to your supply:

1. Mix a squirt bottle, 1/3 white vinegar, 2/3 water. Spray where you do NOT want him to scratch. It should be mild enough that YOU will not notice the smell, but he WILL. At the same time, rub the catnip on HIS things for him to scratch. This way both scents are strong at the same time.

2. Water squirt bottle as several others have mentioned. The BEST training tool, IMO.

3. Double sided sticky tape You can gt it at Home Depot, or Michael's (craft stores). I had to put a strip of that down the edge of my sofa for a time. Looks silly but you only need it up for a week or 2.

Best wishes!