Spider fields.  You know what I'm talking about.  Five or six spider dens all clustered together, usually right between your base and where you want to be at the moment.  Annoyances, for certain, and also completely useless.  Or are they?  Today I'll be teaching you how to make use of these infernal death traps and even safely and easily clear them away, making use of two vital survival techniques.

Hound Cemeteries

While the spider dens are still between tiers one and two, strap on your logsuit and begin a simple spider killing fest.  The first hit should bring out 2-4 spiders, and the second should bring out 1-2 spiders.  Kill them, and be sure to pick up all the monster meat.  Only hit each den twice per day.  After a few days, you should have a lot of monster meat.  Go a little east or west of your camp and spread it all around the ground.  When you hear the hounds' breathing, stand in the middle of this field.  When the hounds arrive, they will be endlessly distracted by the meat, and you have pretty much as many hits as you want on it.  I once killed four like this with a torch.  Work fast though, because they eat more than they drop, and it won't last forever.  Armor is not needed, because the hounds will always target food before mobs.  Make sure this is not by anything flammable, as an effective Hound Cemetery will last well into the occurances of flame hounds.

Colony Wars

Low on silk?  Well, you never will be again!  Once your spider dens are a high enough tier to drop eggs (but not high enough to spawn queens!) make a pan flute and hit one spider den once.  Now play the flute the second the spiders emerge, 'cause the warrior spiders are quick as all heck and need to be put down fast.  The spiders will all fall asleep, and you can hit the den and play the flute again.  Once more, and you should be clear to take it down all the way.  When it breaks, grap the eggs and run.  You can get the silk later, those spiders are gonna be furious when they get up.  Now wait a day for the newly homeless arachnids to calm down, and collect the silk from the den.  Now comes the fun part.  Make yourself a Spiderhat, go to the spider field, and start some Colony Wars!  All you have to do is put on the hat and hit a den.  These spiders are now yours to command.  Attack another colony, but break away before you get there.  Take off the hat.  Leave.  Your work is finished here.

Here's how it works:  Let's say the colony you briefly commanded is Colony A.  As you leave, Colony A will attack the den you told them to, let's call them Colony B.  Colony A attacks Colony B's den.  All the other colonies, which we'll simplify as Colony C, will take no notice, they will only partake if a spider is hurt.  Colony B comes out to defend their homes, attacking Colony A.  Since, Colony B dealt the first blow, Colony C will  assume that they are the traitors, and attack them.  Colonies B and C will fight to the death, but it doesn't matter who wins (spoiler alert: it's Colony C because Colony A will have weakened Colony B) because while they fight, Colony A will continue breaking Colony B's den, only occasionally striking their spiderly attackers.  You can come back in a day or two to collect the eggs and string and to start the next war.

TL;DR: If there are at least three dens, your spiders will win.

When you're down to two dens, stand on the sidelines as they fight, for your spiders will now invariably lose.  When they do, put your Spiderhat back on and have the colony you just attacked attack the colony you just controlled.  Continue you this until one dies, and then take out the last colony while they're weak.  Congratulations!  You just took out a ton of spider dens and have enough silk to last a lifetime.  If you'd like to, replant the remaining eggs, perhaps somewhere more convenient, and start the whole process over, refueling your Hound Cemetery while you're at it.