Following my little article on InSaNiTy, it's only natural that I fix an InSaNe deck. =P
Let's see what we have here...
Hey monkey, i am writing you my deck because i cannot get on the message boards right now. . . .its clogged. . . . The sandslash is Brock's LV34 the
real good one with swift for rocket's zapdos and needle ball for everything else. This deck can own just because it has electric resistance! In case the mighty sandslash goes down I.E. scyther I have sneasel and murkrow for back up! Maybe I should use different back-up, but sneasel stole my originality in deck building! Oh well here is the InSaNe SaNdSlaSH.

x3 brock's sandslash LV34
x3 brock's sandshrew LV20
x3 sneasel
x2 murkrow
x2 cleffa
x4 oak
x4 comps
x4 traps
x4 RSA
x3 ER
x3 SER
x3 item finder
x3 gold berry
x2 eco
x2 lass
x2 bill
x2 IOR
x1 GOW
x1 wrath
x4 dark
x5 fighting                   
Maybe i should take out some ER  or SER for
something else?
Your pokemon lineup looks pretty good, but we could use a few adjustments here and there.  First of all, drop the Sneasel and Brock's Sandslash to two, and drop the Murkrow to one. Then lets add two Hitmonchan and a Magby. Hitmonchan may not be as good as Gligar, but this way we won't have to include DCEs to get the most out of the cards. Magby has been hurt by Wizards' recent ruling that the effect goes away if Magby is benched or ko'd, but its still pretty good against Slowking.
Moving on... your trainers. Definitely drop the SERs. Your energy count is too low to be discarding one for SER. Let's cut the Traps too-with Cleffa everywhere and having to flip to do anything, this card just isn't as good as it used to be. Now we have seven spaces to work with. Up the Bills and EcoGyms to three, and the Gusts to two. Let's add in a Nightly Garbage Run too to help keep you from decking. Then let's cut the Misty's Wrath and a Gold Berry for two Energy Charges. You'll be needing them if your Darkness Energies get removed.
We still have three spots open from the trainers we took out, so let's add a bit to the energy. Add in another Fighting Energy and two Rainbow Energy. You'll need a bit more than what you have to power your pokemon efficiently.
I think I have the numbers balanced out now, try it out and see what you think.
~ Monkey