It's amazing how fast fuel gets to brass tubing in this day and age. It's the nitro that does it and I don't think any nitro we use is made in this country any longer. It didn't used to be that way. At the hobby shop I used to work, we sold a of K&B fuel. It was more expensive, but the competition like Red Max at the time used imported nitro that was cheaper, but would attack brass. To illustrate this, we kept a baby food jar filled with each and a length of brass tubing in it on the parts counter. It only took a day or so for the brass to start turning really cruddy. If you use any Pylon/Sullivan plastic tanks and use the brass tube that is supplied with it, it is at least easy to change, but easy to see the corrosion starting and growing. If we want to fly we have not much of a choice but it helps to flush your engines at least now and then with an after run oil.
Type at you later,
Dan McEntee