I'm 75 RDM and i lived in CN for about a week killing scorps. With /thf i got 1 claw and maybe a shell of doom scorpions and guaranteed 2 claws and 1 shell off of mushussu. Hope this helps.
If you're about Lv50+ and armed with a TH/2, you can easily get 1 claw for every 2 scorpions.
First, go to www.ffxi-atlas.com and look up the map for MoS. In the Maze of Shakhrami, on the first map, there should be a scorpion in G-6/G-7. Kill it and take the right tunnel D. Follow down, and there should be 2 more scorpions in a flock of crawlers. Keep going, and you'll end up at E on the first map again.
Starting at I-6, you can easily hunt down 5 scorpions (1 of which is a Labyrinth Scorpion, lil tougher) down till K-9. When done, enter at point F to reach the 2nd map. On 2nd map, there should be 2 scorpions at I-8. After you're done with those, enter tunnel C @ H-8 to go back to first map again.
From there, go to G-6/G-7 and start the route all over again! If you time yourself right, you can continously kill scorpions without having to stop (unless for resting purposes). From what I see, they have about 10 minute repop time, and be careful of elementals, they are quite a handful.
If this is too tedious, then you can always buy claws for about 1k~ at the AH ;D
*NOTE: Scorps also drop Scorpion Shells, about 1/6 chance from my experiences. Good Luck!
Not only can you farm the claws here, but you can also get bone chips from any of the dozens of skellies and you can get your wind crystals from the elementals. Great place to farm and synth on the spot!