How quickly would a pocket blowtorch ruin PCB traces?
Most likely, the heat of the torch flame will cause carbonization of the plastics in the motherboard &amp; nearby components before the needed solder pools are liquified.

Once you carbonize (or carburize, if you prefer) an insulating layer, it becomes a lossy conducting layer (i.e. it's ruined), so I would highly recommend against ever intentionally exposing a PCB to direct flame.

An alternative that will likely work for you:
Get one of the "pistol grip" type "soldering guns" (like this one or this one) that have the >- shaped wire tip/heating element. Most of those are meant for soldering large chunks of NOT thermally sensitive stuff, sl they produce enough heat fast enough to melt all the solder pools attached to your usb port's housing...and do it without exposing your pcb &amp; other components to fire.