steve is right . if you used a salution to stimulate the rust , then you must nutralize it .
HOWEVER natural rust , done in a sweet box does not need to be nutralized becouse no acids are in volved . simply H2O mixing with irons in the steel .
another thing to remeber is engine olis have rust inhbitors this is why you use alot of oil , then let it set .
but again , if you used a salution like Lorul mountian or plum brown , then you need to nutralize . if you did not , no worries just wash it down with alittle baking soad and water . then re oil and wipe