12-06-2010, 07:26 PM
Gary, here are my thoughts....Keep it 2 inches from the track, glue it good and don't worry. After it has set hard, then run you magnet around. Anything that comes lose will be what you pick up. You will probably run a vacuum over it once it sets too, to remove the loose stuff, and probably have to clean every so often that what little is there shouldn't be a problem. Now, if you get some dirt from around the scrap yard, then I would worry. 
Charlie
Charlie