My dad and I have been laying some grass material and gravel in the downtown area of our layout. As another part of this big “urban renewal” project we’re installing some Walthers cornerstone street lights. When he went to put in the scenicing stuff he didn’t want the holes that have been drilled for the lights to fill in, so he broke a q-tip in half and stuck the stick end in the hole and it worked great. This could also be used if you are ballasting over existing signals, and many other things.
Hope this can be a help to you.