It is important to present the knives back to the customer in not just a safe manner but I think one that stands out a little.
What I do is :
1. Buy a big roll of the brown wrapping paper at Staples, it is like butcher paper. It is about $15.00 but it lasts me a couple of months so it would last you longer perhaps.
2. I wrap the knives up in the paper so that inside the paper each knife is individually wrapped, just a matter of folding the paper over each knife. Keep in mind that the owner will be carrying the whole bundle so you don't want anything to fall out.
3. I purchase some nice paper at a Japanese shop and either on that paper or on another piece of paper I write a thank you note with a brief explanation of how I sharpen their knives. People will either read this with delight or throw it away but in my case, it is just a personal touch that means something to many people.
4. I wrap a piece of the nice Japanese paper over the ugly brown paper. Now in the picture above, I just bought a stencil at a stationary store and some blue ink and I used that as the outer layer. I don't always do that but it went over well.
Keep in mind that people may want to look at their knives before bringing them home so you may have to unwrap the knives and all this work will be for nothing but not really, people still like it.
I used to use foam to wrap the knives but it is not environmentally friendly. This is just the way I do it, use your imagination and make it pretty.