Spiders? Leave them alone, lol, they eat insects not plants.
If you meant to type "spider mites," that's different and they would need to be dealt with. I've found that a good, thorough spray with a shower head or the sprayer on a kitchen sink will remove them from plants. Unfortunately, it may leave some eggs in the soil (if the plants are rooted and growing in soil that you cannot easily/simply remove them from).
If that's the case... What I do is remove them from their containers, blast them from every direction with water as mentioned, shake most of the water off, and then thoroughly drench them and any remaining soil with a product such as Safer's Soap or the like -and then repot them and proceed as per normal.
You can add a thin layer of food grade diatomaceous earth (after the top layer of media dries), which will kill and soft-bodied critters that crawl over it. It's nontoxic. However, it doesn't work when wet.