Questions for Sonus Faber owners

For those of you who own SF speakers with the string grills and/or the string bases, what do you use to maintain the strings? Also, how many of you have had to replace the strings in either the grills and/or the bases?
If you were able to do that, how were you able to do that?
Lastly, does anyone know the typical life expectancy of these strings( which I have been told are made of silk) in normal use. I ask these questions as my SF GH's have the strings and while I love the look, I am beginning to think that they will be a potential problem as time goes by.