Use the mouse or touchscreen to navigate the seas. Stop over in areas where you see trash to pick it up, and then travel back to your seaport. The wharf has a recycling point where you can sort out the litter you picked up during your voyage out on the water. Sort the items, starting from the top-left bin and ending at the bottom-right bin. Then use the collected money to purchase upgrades for your ship! You can for example increase the ship’s speed and carrying capacity.