On 26 July, 14:03, (Andrew Gabriel) wrote:

My Stihl ones says to clean the blade with resin solvent.
The only resin solvent I've found is their own, which is rather
expensive, and no one seems to stock it.

Woodworking shop, router cutter cleaner. Trend do it.

Alternatively a spray of either penetrating oil (not WD40) or brake
cleaner.