Our railway is under a full canopy of trees and other vegetation so nectar, pollen etc from the trees especially some silver birches caused real problems at times when the railway was solely track power. Honey dew from insects (polite name for their droppings) is also a issue. Some years the silver birch nectar is worst than others, in the worst year track could need recleaning after two hours in certain areas. It was then I too adopted the damp thin sponge method like others mentioned above.
In my case I wrap it around a small wooden block as you see in the picture. While our railway is now predominantly live steam and battery power we still do run track power occasionally. Even now I still wipe the track down before a run with the damp sponge if it`s been more than a couple of days since the last run. By doing so firstly I help stop the sticky stuff getting on to wheels and secondly track power continuity is maintained for when needed.
Very occasionally, may be once every six months the good old LGB track cleaning block gets lightly used, but with a twist. First a quick wipe with the damp sponge then the track cleaning block then followed by the damp sponge again to pick up any grunge. A bit pedantic yes but it works and with the railway now having been down for over 9 years so it`s a time proven method!
Oh yes and recently a visiting track powered loco was used and ran with no problem. I was very pleasantly surprised as it had been many months of battery power and live steam use since track power was last used. Granted it was a 4 axle loco with pick up on all wheels but a very good sign than by frequent wiping of the track with a damp sponge is worth the effort
