We had a bad experience with pine marten in our small cabin in the mountains in Norway; they can really make considerable damage. When we came there at Easter one year, we found traces of soot everywhere, and the beds where covered with a mixture of sugar, rolled oats and cocoa. The culprit left revealing signs: there were sooty footprints on the cover of the gas stove. Martins are very good climbers and this one came down from the roof via the chimney and out through the fireplace. Now we have learnt to block the chimney damper and to leave anything edible in tight boxes. It also used the sofa as loo, fortunately, it was cold (around -20o C, indoors) so it hardly left any marks and.
We were lucky, though, one of our nearest neighbours (about 500 m from our cabin) had a visit as well, they had a 7kg cured ham hanging in one of the cross beams in the ceiling. The marten climbed up the wall, crossed the beam and gnawed the string holding the ham. It fell down with such force that two floor boards were splintered and had to be replaced.
Unfortunately, there is no scientific evidence that the many electronic devices on the market have more than a very limited and short-term effect, according to the Danish Pest Infestation Laboratory, the University of Aarhus, referring to German investigations. But hopefully the devices mentioned by Sisyphus were not included in the Germans’ investigations, so good luck to both of you.
Funny though, some people are trying to chase the martens, others are going to great lengths to get a glance of them. I read a blog
https://www.blackislehides.co.uk/blog/pine-martens-bloody-pine-martens which describes a new type of photo tourism offering a hide where you may see martens, if you are lucky; I suppose it is not for free…