Thanks to everyone who replied. Mark, that was a very detailed reply.
I know that Combat is very effective because it completely eliminated
the roaches. Maybe there were some in other apartments that were not
as clean but they didn't effect me.
The ants seem to have disappeared. We are not having as much rain as
before & that might be the reason. That vacuum cleaner technique
sounds super but it wouldn't work with the 20 foot ants..
Thanks

Green Goddess