Your first kit is free, subsequent kits cost 500g.
There are 4 clamming beaches, one for each cardinal direction. You land from the Manaclipper (or the teleport) at the north beach, and there is one Clamming Point there. East and west beaches each have 2 points, and south has 3.
The points do not move and are reusable after 10-15 seconds.
Initially, the goal of Clamming is to dig up as close to 50pz as you can without going over. If you go over, the clamming bucket breaks, all items are lost, and you are forced to start over with a new kit.
When ready, find and click on a Clamming Point and select the option to "dig".
Upon digging you can find the items listed below. Each weighs a set amount of ponzes. You can continue to dig until either you turn your bucket in and collect your catch, or your bucket gets too heavy and breaks.
At any point prior to your bucket breaking, you may turn the bucket in to Toh Zonikki, at which point you will receive your catch. You will need to buy another kit from Toh Zonikki for 500g to go clamming again.
However, if you catch at least 45pz in your 50pz bucket, Toh Zonikki will offer you the option of upgrading your bucket to a 100pz bucket and continue clamming.
Then, if you catch at least 95pz in your 100pz bucket, Toh Zonikki will offer you the option of upgrading your bucket to a 150pz bucket and continue clamming.
If you catch at least 145pz in your 150pz bucket, Toh Zonikki will offer you the option of upgrading your bucket to a 200pz bucket and continue clamming.
If you keep clamming past this point it is possible that you will get the message: "Something jumps into your bucket and breaks through the bottom! All your Shellfish are washed back into the sea..." If this happens you lose everything. The "something" that jumps in your bucket is only seen very momentarily, but looks a lot like the Alraune that inhabit Purgonorgo Isle.
You will always start over with a 50pz bucket, even if you handed over a 200pz bucket.