Brown recluse spiders typically have a lighter brown abdomen than legs and body, so no doubt you are mis identifying your spiders, and recluse are just not that easy to identify.
There is a much greater chance your spiders are harmless,
Todd and John R both have good answers.
It's not weird; most of us tend to worry a lot about things when we don't know much about them - that's what people do. However, as Todd points out, almost all brown spiders are _not_ Recluses. They're called "recluses" for a reason; they don't tend to go strolling around out in the open in broad daylight very much, whereas most of the other sorts of brown spiders are more than happy to wander out in public. Yours don't sound like recluses, and luckily for you, there's an easy way to find out - take a photo, (squished or unsquished), post it up on one of the free web-hosting services like Flickr or whatever, and post your question here with a link to that photo. There are several of us who post here that will probably be able to tell you what it is, or at least what it isn't. It helps if you take several photos from different angles, but at least one from directly overhead, and as clear, well-lit and in-focus as possible. It also helps if you say where you are, and what part of the house the spider was in, and what it was doing.
As for the rest of your question, there's nothing to worry about from a squished spider; spider venom is only a problem if injected, and even then, only from the very few spiders that have venom which affects humans. So, in other words, no problem. I don't think you need to be killing every spider you see, but it's your call; we all have our sensitivities, although I'd rather not let my fears control me when I can control them. Anyway, you're doing the right thing in asking about them, although of course, having a photo or a very detailed description gets you farther.
Well, first there are no "poisonous" spiders. Almost all are venomous. The difference is that spiders have to bite you to inject venom.
Secondly, you "feel" that they're brown recluses? What are you going on besides that they're brown? Here's a good, complete guide to identifying brown recluse spiders.
http://spiders.ucr.edu/recluseid.html
And lastly, the venom won't spread on the ground in any significant concentration. Spider guts are "safe".
You most likely don't need to be destroying these spiders.
I went on a site on this topic but can't remember the name, If I'll remember I will let you know.
They go squish and join the rest of the dead spiders in the spider cemetery !
They die for sureeeeeeeeeee.
I've been seeing a lot of brown spiders recently (light brown bodies with a dark brown butt) and I always squish them. I feel like they're brown recluse spiders, and I was wondering, if I squish a poisonous spider, will it's venom spread on the ground? Is it safe? Sorry if it sounds a bit weird, but I get paranoid easily and I tend to over think things. Thank you!
