How do I pre-process import data for importing computers

I am importing order information from another system just using csv files.  For some reason for Mac computers the spreadsheet has an extra character at the beginning of the serial numbers, which causes a problem since once we image these up and they report they are not the same machine and do not get merged together.

For example here is a row of data  and the mac computer serial number actually starts with the C so it is adding an S to all of them from our vendor

collapse;width:569pt" width="758">
Serial NumberModel (Manufacturer)Manufacturer (Manufacturer) collapse;width:665pt" width="886">
SC02xxxxxxMACBOOK PRO 15IN 2.6GHZ I7 256GB SILVER W/TOUCH BARAPPLE - SYSTEMS 

I do see that I can pre-process the data using a funciton of sorts in the console, but I am not familiar with how the function has to be created.  Basically I would like if the manufacture is like apple then strip the first character of the serial number

Any help is appreciated