How to clean the USB cable with some points of brown red rust at usb end?

hello all

I have an old WD external hard essential 250 GB with usb 2.0 contains my all old data

it has been couple of years since i use this hard last time, as i do not have ability to buy another new bigger one until recently

does any one know how to clean the usb cable of the external hard essential 250 GB, I found out that that rusty small spots present on the USB cable end (usb end at the corner of rubber black cover and metal) affect on the connection of the usb cable to the laptop

how you could help me in that problem
please I seeking your kind guidance and help

i will be so appreciated if any one has some answers to my problem