The bristles on the Etude House brush are synthetic, so I didn’t have qualms about using the cleanser with it. Do not use the detergent with delicate brushes; it may damage them as it is not formulated for brush-cleansing.
I recently washed a cream blush-smeared sponge and a foundation-stained Etude House Dual Fibre Cheek Brush with some Daiso Detergent for Puff and Sponge (the name cracks me up a little – without the esses, it sounds like a soap for puffing and sponging).
I squirted some of the liquid into an Ikea Galej tealight holder – the perfect size for washing these items – and diluted it with some water before dipping the tools into the mixture.
As I was formatting the photo above, I realised that the brand’s name is upside down on the brush, thanks to my left-handedness. ;)