Use Mobile Fidelity lp #9 stylus cleaner. It comes with a very soft brush and a hard brush. Use the soft brush along the top of your cantilever. It will put no dangerous pressure on the cantilever.
I do this about once every year or two because I believe there is a slight concentration of alcohol in the fluid and I don't want to impact the glue that holds the stylus in place. Whether cleaning your stylus or the cantilever, I have had only great results over the last 10 years or so. I use this for my Dynavectors and Shure. Re my Lyra, I use Lyra SPT stylus cleaner but I have not used it on top of my cantilever, only on the stylus. That might work on the top of the cantilever as well, but I simply have no accumulation on the Lyra since I purchased it---so I can't say.
Either way, I think a fluid will work better to dissolve the impurities than even a minor scrub with a harder substance.