tom wrote:
Remove their food sources, and they'll leave. Tom

...

To elaborate on that:

Spiders eat insects. There must be insects in your shop, or else
the spiders wouldn't be there. Get rid of those other bugs that you
don't mind and you won't have spiders to worry about.

I had a roomate in college who worked as an exterminator.
When he got a call about spiders, he looked for some other
bugs and killed them.

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FF