Car engine injector cleaner and almost any add-it-yourself fuel additive.

I don't know how valid this is, but I heard county and district councils use government bonds to secure more favourable loan terms. When Liz Truss upset the UK bond market the cost of borrowing rose as the value of their bond assets dropped. The county council where I live is now spending as much on servicing debt as it is on fixing roads. (Roads, although not the most important responsibility of local government, are a visible indicator of their capability.)