Meter cluster problem

Hello,

I recently saw a bottle of so called fuel line cleaner(cant remember the exact name) at an car accer shop selling for RM12. It says that im suppose to add it in my fuel tank and it'll clean the fuel line and carburetor or something and lower my fuel comsumption, increasing fuel efficiency. Just wondering anyone out there used anything like this before? Im having doubts about it and im scared of adding these kind of addictives into the fuel, scared it might cause trouble to my engine...