[Delta 21]

Aerosol brake cleaner works great on the ones that think they are fast or are hiding out of normal reach. It knocks the go right out of them. Flames are optional.

[pax_et_bonum]

For spiders, flames are not optional.

:-)

[ExSafecracker]

Black Widows are very common here in Southern Arizona, I dealt with them for years as a service tech. I was bitten once and it was pretty painful.
After that I made sure to have a can of WD40 at the ready when I opened an equipment housing.
I think they breath thru their skin, the oil coating on the skin kills them muy pronto.