Thanks for that info bambam,
Don't recommend killing spiders in the garden orangetom, they kill tons of bugs, but if you want to kill them in your house or other areas, Here are some tips from my natural pest control book.
cedar chips repel spiders, as does the herb pennyroyal sprinkled around.
To kill them, mix 1 oz. table salt to a gallon of warm water and spray them, or 1 drop of citronella oil to a quart of water.
This is the condition under which I asked that question.,,
We have a little place where we go from time to time but let the boss man know and our cell numbers. It is a little lean to...with heavy drapes to keep out the wind and even some of the cold.
But we have discovered we are sharing it with a black widow spider we have named Dorothy. She hangs out on the ground level behind a 55 gallon barrel which is cocked up slightly feeding on the passing crickets and other bugs. She often goes underneath this barrel. We know we are going to have to put down Dorothy or eventually she will have lots of little Dorothy's.
The barrel is tucked in there closely to other equipment's so we need to be careful about moving it and not knowing wherein goes Dorothy in her escape.
I have purchased a type of spider spray and have not tried it to date. I'll let you know how it works out. Apparently spider spray is a different formulation from regular insect spray.
Understand about spiders in the garden ...same thing with snakes...they handle lots of other bugs and critters...birds eating lots of different insects too.