It must have been decades since the last I saw this modern gadget that was part of the bathroom, where we would use to help us rub off the dirt, probably using the AXE Brand bar soap. The grooves helped to trap some of the soap onto the clothing and hence helped to create a lather.
It was fun to watch Mum doing the scrubbing or just using the hands to rub the clothings off the groves of this "suay-sa-pang" (Washing Cloth Wood as literally translated from Hokkien), resulting in plenty of soap lather. From time to time, Mum would dip her hands into a pail of water to splash a little on the drying clothes as the water ran off. Often, Mum would sit on a small stool (ah, some of you might have seeen hawkers selling from real small stools to tall ones, as they walked from house to house), which gave her a good leverage.
As we grew bigger and Mum had to go and work to supplement income - talking about dual income families, but with more kids than these days - we had to take over the duties. Amongst brothers and sister, we divided our chores, washing clothes and preparing meals.
Using the bar soap (versus the detergent of today) and the scrubbing board, we tried to make the clothings as clean as possible. In a less than clean environment in those days, I think, the clothings were dirtier than these days. Sweat (yes, on aircond!), dirt and possibly after days of wearing the same clothing agan and again (no, not like one per outing these days), it was a challenge. White shirts just cannot stay white! So, we use the "lam-chi" by putting the powder into a pail of water to make it blue and then putting the white shirts in them to give a light bluish hue. And to make the shirt lasts longer and probably less likely to get wrinkle, we put the shirts into a pail of starch before handing them in the sun.
The final part is to iron the shirts with a charcoal iron. Ah, but that's another story. Ah, someone has decided finally to part with the scrubbing board.