track cleaner

[airtrain]

Hi everybody.
   I'm new to the forum and returning to the hobby after 25 years away. Oh boy, how things have changed. I received a Bachman 16301 M.O.W. tank car track cleaner for Christmas with no instructions on how to use it. My first question is do I use this dry or with track cleaner fluid? I used it dry and it really helped on my 25 year old track but got dirty very quickly. Is there a way to clean the pad or do I need to replace it. Replacements seem a bit costly if needed every time it gets dirty. I would apperciate any help anyone has on the best way to use this car. Thanks in advance.