Oil additives: Yes or No?

[richi]

The nice people who run our oil syndicate swear by additives for reducing soot, etc. They recommend Exocet, but I've also heard good things about NBS Phoenix.

 

What's the one, true thinking? Useful or snake oil?

[Temp]

I never use it and only get the boiler cleaned/serviced every other year. Never seems very dirty.

[Nickfromwales]

Never heard of it or promoted its use. 

Get your boiler checked for clean combustion so you know it's mixtures etc are set up right and carry on without it afaic. 

[Onoff]

Just sounds like Reddex for diesel cars. I bet you could use that tbh. Or Wynns etc equivalent.