I certainly wouldn't canvass or leaflet at this present time. I don't think you'll get any work but you could easily end up with a bad reputation. Common sense dictates!
I would get a part time job delivering food (get some money in) then I would hit facebook, local community groups, whatsapp groups and any other social media you can think of. Let them know you are still working (and safely!). Also offer to clean fascias, soffits and gutters, conservatory roofs etc. (no inside work at all).
Luckily, i've not lost a lot of window cleaning work due to the virus but my add on's have really taken off at the moment.
FSG cleaning, connie roofs, pressure washing, soft washing.
It might be worth targeting the add on work as well, to get some money in.