Take the A862 road from Inverness towards Beauly, then after 10 miles turn off onto the A831 down Strathglass towards Struy and Cannich. After a few twisty miles you'll pass Aigas golf course, then after approx another 3.5 miles look for a white & black wooden fence on the right side of the road (just before the small sign for Erchless Castle and about 1 mile before Struy).
Park at this white and black wooden fence and go through the iron gates and along the path a short way, climbing 2 wooden steps. A ridge runs from here to the right. Follow it's crest for 48p (paces) to a birch tree which leans out across the pathway on the left.
From the birch, go 16p on 152 degrees to a mossy mound which is covering the stump of a fallen tree. Around the far side on the stump, a 'cave' is made under the roots of the fallen tree. In the left hand side of the 'cave', behind a couple of small rocks, you'll find the polecat hiding.
Before you leave, go up the pathway from the gate, about 200m to a clearing and the Clan Chisholm burial ground. A peaceful place.