Here is a simple way of adding rust and rust stains to your models... 1. Take your model and remove bogies. 2. Spray the model with thinned down flat white acrylic paint. If you don't own an airbrush, this can be done with a paint brush. Just keep the strokes vertical. Hopefully when the hand painted coat has dried, there will be no paint brush streaks. 3. Give the model a coat of matt clear. This can be aerosol/rattle can or a product like Dullcote. 4. Next is to mix some brown acrylic with black acrylic to make a dirty colour. Apply this around the seams, rivets, along the very top of the side walls and the base where the walls meet the chassis. Even the undercarriage can be painted with this. 5. Apply another light coat of matt clear. Next stage is adding rust and streaks. This is done using Burnt Umber artist's oil paint. 6. When this is thoroughly dried, add small dabs of burnt umber along the top of the wagon. The oil can also be applied along the rivets, seam joins and along the bottom of the side walls where rust stains would gather. or do full panels like this... 7. Whilst still wet, use a cotton bud to remove excess paint. When doing this, use vertical strokes only as horizontal strokes will ruin the finish. If you are doing a variety of wagons, change the applications of burnt umber to represent different weathering extremes. The oil paint will require approximately 48 hours to cure, longer during the colder months of the year. So, there you go. A simple method of adding rust stains to your rolling stock. I'll follow up this thread with bogie weathering and adding a few extra weathering details to the above wagons using paints and powders. Cheers, Gary.