Thanks Julia, if bull a few points using the etched chairs and was using Carrs liquid fluxes and 0.7 solder bolls but changes to liquid rosin flux because of the corrosion issue so ofnot cleaning the flux after use because the point was constructed on a Templot printout and every time I had been soldering I ended up with a cough.
I tend to build track in small batches so can't completely clean the sleepers for the next stint.
David N