Above is a picture of the one tool I have been using more than most, and it cost nothing and was made in about five seconds; a couple of inches of .20" wire taped to a four inch piece of 5/32" square wood. I use these wire sticks to apply glue where the smallest amount is needed, as in the sidewalk cracks above to which scenic material is applied with a tweezer.It's also useful for applying glue to fill small gaps or to the bottom of figures to glue them in place. To apply rust bleeds and blotches to detail castings or rolling stock, I've been using it to apply small dots of Burnt Sienna or Raw Umber oil paints, dragging them down with thinner. (to see this used to great effect, check out Scott Mason's Weathering Freight Card DVD's). You could also use a nail, but the length of wood gives it a handle, a better feel more like a pencil, saw you can draw with the glue and just have better control.
If you use Micro Glaze or Gallery Glass for window glazing, you can also use it to apply the material into window panes.
