The product we use has a coating on the active ingredient that does a much better job of sticking to the hairs of the spider. The brown recluses have hairy legs so when they walk through the product, it clings to their hairy legs.
We also use glue traps / sticky traps when dealing with brown recluses. There are 2 purposes in doing this: 1) we can monitor where there is more activity and pay special attention to that area when treating the home; and 2) they stick to them and die, claws and hairy legs and all! Bugs that get caught on sticky traps attract more bugs.
An effective way of treating for brown recluses is to dust the attic. This is when a technician takes a machine into the attic and very briefly turns it on, spreading dust up into the entire attic. This then leaves a fine dust throughout the attic that is harmful to brown recluses.