Translation of salvage in German

Since Joseph is convinced of the coming success, he suggests to leave the machine in Canada for another 2 months (at no cost of course!). I think that they learned a lot through your project.
The advantage of this change is that: 1. it improves the response time after every asked word by double. 2. Some do not want to save their lessons, they just want to test it without results being collected...
I was surprised that he charged 5 dollars extra (a total of fifteen instead of ten), because he had to take us to three different locations. I did not buy the whole thing and gave him ten bucks.