Birch tar is said to be incredibly effective at getting rid of slugs, snails, and other molluscs. A study from 2010 showed that birch tar oil could repel slugs and snails from fences and plant pots, and had especially long-lasting effects when mixed with Vaseline. These pest-repelling effects are most likely due to birch tar’s strong and distinctive scent. Using a little birch tar oil in your garden or home can help to keep it free from slugs and snails without producing toxic effects on the surrounding environment.