... furniture,the surface of the plastic cement ,it is water-proof & acid and alkali-resistance abrasive ( home-made sponge) sponge abrasive uses ... plant the sand on the sponge,it is a polishing material,of course it could absorb water,it can be made ... , furniture,the surface of the plastic cement ,it is water-proof & acid and alkali-resistance ,can be used again & again