Games Workshop's Warhammer is a war game played with miniature armies. Warhammer is as much a hobby as it is a game, as players need to paint the miniatures they purchase. Games Workshop branched Warhammer into two time periods, with Warhammer set in a fantasy medieval era and Warhammer 40K set thousands of years in the future. Details such as rust are added to miniatures to increase realism.
Paint your miniature with the colour patterns you have chosen for your army. Allow paint to dry completely. Drying times depend on your specific atmospheric conditions.
Paint the part of the miniature you want to appear rusted with the Blood Red or Red Gore shade of Warhammer paint. Allow paint to dry completely.
Dip a detail brush into Terracotta or Scorched Brown paint. Use a paper towel to drain much of the paint from the brush. Paint on top of the red paint you applied in Step 2, so that it is only slightly visible. Allow paint to dry completely.
Use the technique in step 3 to apply Bolt Metal Gun or Mirthril Silver paint on top of the Terracotta or Scorched Brown paint until satisfied by the appearance. Allow paint to dry completely.
If you want the appearance of rust on top of a metallic surface, such as armour, use the colour of the armour in the last step instead of the Bolt Metal Gun or Mirthril Silver paint.