Buying a new tank is the quickest and best way to resolve this issue, but with older cars this is not always possible. There's a load of different guides and info online, people recommend a range of approaches.
I'd just bought a new tank, which left me with a dirty one to play around with.
This is what I started with, it'd sat empty for a long time so everything was properly dried and horrible.
I started with a couple of teaspoons of baking powder in hot water. This got some lumps of crap out, but didn't shift much of the grime.
Second I got some cleaning solution from work. It's a heavy duty detergent and high pH. Made a bucket of the stuff up and left it to soak for a few days. Results were disappointing, it didn't seem to do much.
Next I decided to switch to Acid cleaner, I had some leftover citric acid powder so put that in. Pretty quickly it was clear alot of the crap was being dissolved.
I left it for a few days and it looked promising. A lot of the crap was gone, there was still some staining remaining.
As citric acid seemed really good I tried a stronger acid. I got some brick acid from the local builders merchant and left it sitting in that for another couple of days.
Nothing really happened, perhaps everything that acid would remove had already gone.
I washed the tank off, then took a bottle brush to it. The remaining grime was brushed off pretty easily. I don't know if it would always have come off so well or sitting in chemicals had loosened them off.
You can't get into every corner with a brush, leaving some dirt. You can also see, compared to a new tank the colour has not been changed, even sitting in fairly strong acid.
The final thing to test was a dishwasher tablet. Stuffed one in along with some hot water and left it overnight. This worked surprisingly well, the last bits of grime in the corners was cleaned away.
Internally, the tank is really clear.
It seems like the best approach to cleaning one of these is try to clear as much stuff away with a brush first, then stick a dishwasher tablet in it and leave it for a day or two.
I'd just bought a new tank, which left me with a dirty one to play around with.
This is what I started with, it'd sat empty for a long time so everything was properly dried and horrible.
I started with a couple of teaspoons of baking powder in hot water. This got some lumps of crap out, but didn't shift much of the grime.
Second I got some cleaning solution from work. It's a heavy duty detergent and high pH. Made a bucket of the stuff up and left it to soak for a few days. Results were disappointing, it didn't seem to do much.
Next I decided to switch to Acid cleaner, I had some leftover citric acid powder so put that in. Pretty quickly it was clear alot of the crap was being dissolved.
I left it for a few days and it looked promising. A lot of the crap was gone, there was still some staining remaining.
As citric acid seemed really good I tried a stronger acid. I got some brick acid from the local builders merchant and left it sitting in that for another couple of days.
Nothing really happened, perhaps everything that acid would remove had already gone.
I washed the tank off, then took a bottle brush to it. The remaining grime was brushed off pretty easily. I don't know if it would always have come off so well or sitting in chemicals had loosened them off.
You can't get into every corner with a brush, leaving some dirt. You can also see, compared to a new tank the colour has not been changed, even sitting in fairly strong acid.
The final thing to test was a dishwasher tablet. Stuffed one in along with some hot water and left it overnight. This worked surprisingly well, the last bits of grime in the corners was cleaned away.
Internally, the tank is really clear.
It seems like the best approach to cleaning one of these is try to clear as much stuff away with a brush first, then stick a dishwasher tablet in it and leave it for a day or two.
