The present invention relates to a method of concurrently creating a frictional washing surface and joining the frictional washing surface to the surface of a housing material for a sealable waterproof bag for washing one or more textile items, the method including: i) applying a quantity of a polymer to the surface of the housing material for the sealable bag; ii) positioning a tool on the quantity of the polymer, the tool including a void region containing depressions and/or projections complementary to the shape of the frictional washing surface; and iii) applying heat and/or a current and/or a frequency to the tool to soften the polymer and allow it to form the shape of the frictional washing surface and concurrently join the frictional washing surface to the housing material for the sealable bag.