The invention discloses a method. According to the method, paste is used for sheltering at least one hole in a component, and the holes are formed in the surface of the component. The method further includes the steps that a coating is formed on the surface of the component, and the paste is removed so that at least one open hole can be left in the surface of the component with the coating. According to the step of paste removing, the paste is made to make contact with water. The paste comprises, by weight, approximately 40%-80% of filling materials, approximately 0.5%-20% of an inorganic binder, approximately 0.5%-15% of a polyhydroxy compound and approximately 5%-25% of water. The filling materials include the first material and the second material. The first material comprises alkali metal doped aluminum oxide, zirconium oxide, titanium oxide, silicon dioxide or a combination of the alkali metal doped aluminum oxide, the zirconium oxide, the titanium oxide and the silicon dioxide. The second material comprises silicate. The weight ratio of the first material to the second material is about within the range of 1-10.