Sounds mean, but the old books say it works. We are going to try it, but we are going to try it gently. No use killing the trees after all the work we've put into them, now is there?
First things first, we need to gently scrape the bark. Some recommend chicken wire, some recommend an old hoe. Basically, get something metal and gently scrape away some of the oldest bark. Why? You are ridding the tree of little insects and eggs that have built up over time. If you start to get to the white or green living flesh of the tree, you've gone too far. Just give it a scraping or rubbing like you would a kid after playing on the beach. You don't want to rub their skin raw, but you want to get as much sand off as possible.
Secondly, you get to hit the tree. You know how you kind of wack your kids to get the sand off of them? Ok, no? Well, you know how in Scandinavia they make you jump into ice cold water then hit you all over with branches to get your blood moving and "invigorate" your skin? Still no?
OK, well they do and that is what you are going to do for your old apple tree.
Give it a good whacking along the trunk with a stick. Wake that old girl up and get her ready to produce some fruit!