I had an Ant colony in my last van, but could remove it. My new van is higher and i build wooden stairs, so my dog can get in. Problem, the ants use it as well. Strong smells like cinnamon, mint or vinegar do not work and are only temporary. I have a small vacuum and can suck them away, but i need something to discourage them from taking the stairs. I know ants avoid rubber, at least that's what i assume, because they never use the tires. But coating the end of the stairs in rubber does not seem to easy. I know in the US they have some spray "Plasti-dip" (or similar) but i've never seen that stuff in the EU.