milli ohm meter query

[Paul Perry]

I'm doing a lot of hunting for shorts on PCBs at the moment.
Naturally i can't afford a 'proper' millohm meter (and I only
need somethng going up to say 100 millohms full scale.

Is there any way I can adapt my cheap digital multimeter for this,
with some kind of little external add-on ckt?
Accuracy isn't important.
It  has a 4 ohm scale.

paul perry melbourne australia