Talon ant gel available at Woolies. Comes in a syringe and a small dob in the upper corners of the van works a treat. We have found it is the only thing that seems to work on the small black ants consistently. Easily applied, no mess and one syringe lasts for quite a few doses as you only need a small dob. We keep some in the van at all times.
Again I say; get them before they get in!
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Cheers, Richard (Dick0)
"Home is where the Den is parked, Designer Orchid Special towed by Jeep Grand Cherokee Limited"
"4x250W solar panels, Epever 80A charger and 3x135Ah Voltax Prismatic LiFePO4 Batteries".
My approach is a little more specific: I watch where the ants are walking (they leave a chemical trail for other ants to follow) and I interrupt that trail with the gel. The good part is that the gel will stick to any surface (walls, ceilings) and won't be absorbed by the material - I use it on brickwork at home too.
I haven't had any ants remain after a couple of days.