Please see information from Cornwall Council:
Our main line gritters are out on the precautionary salting network ensuring it is open and safe for business (essentially the main A and B roads and some C roads/schools/hospitals which can be viewed on mapping here).
We also aim to treat routes to villages not on the precautionary salting route once the precautionary salting network is treated/open/safe. Given the priority is to keep the precautionary salting network safe and open for use, it’s unlikely we will be able to respond to all requests for salting minor roads but we will direct resources to problem areas where possible. During the current extended cold snap the advice is to travel only if necessary – see the press release:
In terms of salt bins, provision of new bins and secondary refills were devolved to Town & Parish Councils several years ago with Cornwall Council only funding the initial refill in a winter season. The normal protocol being secondary refills and repair or replacement is met at the Town/Parish councils expense. However, it has been agreed to depart from this given the extended cold snap and a further refill will be funded by Cornwall Council for all existing grit bins and will be progressed within available resource in the short term.
I have included the winter maintenance factsheet below which includes further useful information.