how to get rid of sea-urchins

I've got a few really nice sea urchins in my tank. But they are growing pretty fast and reproducing fast too.
How do I get them out? I don't like to get stung

And, while I'm at it. Anybody have any tricks on how to catch crabs? I've got quite a few in my tank and will try to get them out soon, but haven't got a plan yet. I will post some pics though first as I'm not sure if I need to get them out. They are kinda cool

 

how big r they?...can u use some pliers? or like tongs? lol

 

well, I don't know.
I've got 2 different kinds. One has a small body and small spikes. about 2 inches across with the spikes I guess.
The other one has a very small body and reaaaaaly long spikes. About 1/4 inch body and 4 inches across with spikes maybe.
They do look cool, but I just got too many by now.

 

is this a reef tank?...because if so not many urchins r reef safe...im pretty sure that the one with the small body with long spikes is the long-spined sea urchin...i think Diadema spp..that one is not reef safe the other one...im not sure...mayyyybe...the rock-boring urchin echinometra mathaei?...what the the color or the small one with small spines?

 

the short spiked one is all black. the long spined is black but the spikes are black and white striped.