How can sawdust be effectively used as wood filler?

Sawdust can be effectively used as wood filler by mixing it with a binding agent, such as glue or resin, to create a paste-like consistency. This mixture can then be applied to the gaps or holes in the wood surface and allowed to dry. Once dried, the sawdust and binding agent will harden, filling in the imperfections and creating a smooth surface that can be sanded and finished to match the surrounding wood.