No pinion seal on donor rear end, clean area and go?

[jordanblea]

Hey there fellas, first post here thanks for all of the info that I have been able to pick thru and get me this far! Anyways I am replacing my 12 bolt rear with another from the wrecking yard and am about ready to put everything back together. Being my first rear end job I wasn't 100% on what does or does not need to be on it. Turns out there is no pinion seal and it is all dirty where the seal goes. What needs to be done, can it just be cleaned out with break cleaner? I am here looking for direction, so please and thank you! Sorry if this is the wrong place to post. Thanks again!!