Does USDA accept re-packaging of RTE cold cuts packages (salami, prosciutto) which are out of weight, dirty sealed and so on and so forth once they leave the processing room?
I was thinking to get them externally sanitized prior to re-entering in the slicing room.
Yes, you can sanitize a package and reopen it to rework the contents. What you may need to do to satisfy your inspector and comply with your own sanitation policy is have different people perform different parts of the process. X person removes the secondary packaging and applies sanitizer to the primary package, then Y person who touches only the now sanitized package can open it and separate the product from the package.
We have to do this kind of rework operation occasionally when a problem isn't detected early. It's one of the drawbacks of maintaining different levels of sanitation in separate departments.