Well OK , if it's ethical to splice left over cable rather than a complete run from the electrical panel to the range/oven then I assume it's also OK to use { in this same house } old breakers just clean them up a little bit first - maybe even old junction boxes - wire nuts - covers etc. and that list can go on an on....
Are you asking about used material or simply dusty new material? If you are asking about the latter the answer is yes, it's perfectly fine?
Roger