Good quality seal ink is often sold along with a small paddle called, in Chinese, yinzhu 印箸 or “seal chopsticks.” If you purchase seal ink in a ceramic container it will usually be flattened with a plastic cover over it when new. Take off and throw away the plastic and then, using the supplied paddle, roll the ink into a ball. Ink bought in packets will also usually include a paddle with which you can scrape the ink into your container and then roll it into a ball. If you don’t have a paddle you can buy them from Chinese art supply stores or online or try making your own. As you use your ink the ball will naturally flatten out so you should periodically use the paddle to scrape it up from the sides and bottom of the container and roll it back into a round shape.
I read somewhere that a seal paddle should not be made of metal, but there was no explanation of why this should be. If you purchased your seal ink in one of the small metal tins, don’t bother to form it into a ball since you won’t be able to put the lid back on. You could transfer the ink into another, larger, container but it’s probably not worth the effort as the ink in tins is not necessarily of the best quality. Besides, the whole point of ink in tins is portability and not studio use.
Although hard to find in other than the standard straight shape, a seal paddle can be in almost any shape or size. In old China these were sometimes made of ivory or other materials, though today cow bone is most common. Look for one at least two or three inches long as anything shorter is hard to use without getting ink on your hands.
The picture below (downloaded from the internet) shows a pair of decorative seal ink paddles.
