Before the invention of the cotton gin, how were seeds removed from cotton fiber?

Before the cotton gin was invented by Eli Whitney in 1793, cotton seeds were removed by hand. This presented a problem, particularly for planters in Georgia and South Carolina, who began to plant larger crops to meet an increased demand in textile mills in New England and Great Britain. The process of separating seeds from cotton was time-consuming when done by hand. The cotton gin eliminated this aspect of human labor, allowing slaves more time to pick more cotton.
Within a few years of its invention, the cotton gin fueled the massive economic growth of the South. Cotton cultivation did not require a lot of land or large amounts of money for investment, allowing poorer, smaller farmers to shift from the cultivation of crops like tobacco—which was difficult and had seen a decline in demand—to cotton. Production increased to meet high demand. Land was cleared to build cotton plantations and exports steadily increased. Because demand was so high, cotton was still purchased at high prices.
Increased demand for cotton created more demand for slaves. By 1803, no less than 20,000 slaves were imported into South Carolina and Georgia. Merchants in New England states also supplied Southern traders and planters with black slaves. The slave trade was abolished in the United States in 1807, but continued illegally until 1860 when the Clotilde docked in Mobile, Alabama with more than 100 West Africans to be sold.
https://www.theguardian.com/books/2017/dec/19/zora-neale-hurston-study-of-last-survivor-of-us-slave-trade-to-be-published