Dirt in the engine

[StaffieLuva]

I have a lot of dirt in my tank that seems to block the petrol coming through (it judders alot)
Would you advise using Red X?

The last time i used it i put a whole bottle in a tank with very little fuel in and totally wrote car off.
I've had so much advice since then (use when engines hot, don't use when hot, fill car with fuel 1st, dont fill tank 1st)

Now i don't know if to trust it or not and if so, what is the best way to use it? I know not to use whole bottle again.

Thanks for any help possible

PS Cars a Rover 200