Easy way finding Black Sludge?

Question

Is there any easier way to find Black Sludge in DP without having to catch a Croagunk or Toxicroak?

Answer 1

Well, the only way you can get it is through Croagunk and Toxicroak - you just need either:

• Pokeballs
  OR
• An item stealing move

You can easily get Pokeballs, of course. $200 at the Pokemart. Woohoo! x)
However, for an item stealing move there are a few, such as:

Thief (will not work if your already holding an item)
Covet (will not work if your already holding an item)
Trick (it will switch your item with the opponent's, not steal)

And that is all. :3
When you click on the links, you can see which Pokemon knows that move.

You can either catch the Pokemon or take the item from the Pokemon, if you wish. Remember, only Croagunk and Toxicroak have these items. It's also a 5% chance it will appear on the Pokemon. (1/20)

If it becomes all too annoying for you (don't worry, it's okay to give up) then you can steal the Black Sludge from Trainers. Unfortunately, though, all trainers that have the Black Sludge are in HeartGold and SoulSilver. If your willing to trade, all the trainers are on this page.

Good Luck - Hope I helped. :)
Sources: All linked pages

Answer 2

What I do is catch a Pokemon with Frisk (Shuppet and Banette work fine, or others with Frisk) and a Pokemon with Compound Eyes (Erm, Butterfree???) and have the Pokemon with Compound Eyes in the front of the party, fainted. The Pokemon with Frisk should be next. Now, you go hunting for Croagunk, and you may find the Black Sludge very early, with luck. The second option would be to trade.

Hope this helps!