A method for refurbishing a tap-hole, said method comprising the following steps: - making a tap-hole channel trough a tap-hole block in a lower section of an arc, blast or smelter furnace, and - restoring said tap-hole channel to form a refurbished tap-hole; characterized by the following steps: ∘ detachably connecting a prefabricated, hollow, refractory tap-hole insert comprising a shell to a clay gun, wherein said tap-hole insert comprises i. a first end and a second end in axial direction, wherein said second end is blocked. ii. an opening arranged on said first end, iii. a hollow passage in axial direction, wherein said hollow passage is accessible through said opening, iv. a plurality of lateral through holes, aligned in a longitudinal direction of the shell, with a constant interval in-between and covering 10-25 % of the shell of the tap-hole insert and arranged in said shell such that said through holes are in fluid communication with said tap-hole channel, ∘ inserting said tap-hole insert into said tap-hole channel, wherein said clay gun is fluidly coupled with said tap-hole insert and said tap-hole channel, ∘ injecting a grouting material from said clay gun into said tap-hole insert and through said through hole into said tap-hole channel and, ∘ disconnecting said tap-hole insert from said clay gun. - making a tap-hole channel trough a tap-hole block in a lower section of an arc, blast or smelter furnace, and - restoring said tap-hole channel to form a refurbished tap-hole; characterized by the following steps: ∘ detachably connecting a prefabricated, hollow, refractory tap-hole insert comprising a shell to a clay gun, wherein said tap-hole insert comprises i. a first end and a second end in axial direction, wherein said second end is blocked. ii. an opening arranged on said first end, iii. a hollow passage in axial direction, wherein said hollow passage is accessible through said opening, iv. a plurality of lateral through holes, aligned in a longitudinal direction of the shell, with a constant interval in-between and covering 10-25 % of the shell of the tap-hole insert and arranged in said shell such that said through holes are in fluid communication with said tap-hole channel, ∘ inserting said tap-hole insert into said tap-hole channel, wherein said clay gun is fluidly coupled with said tap-hole insert and said tap-hole channel, ∘ injecting a grouting material from said clay gun into said tap-hole insert and through said through hole into said tap-hole channel and, ∘ disconnecting said tap-hole insert from said clay gun. ∘ detachably connecting a prefabricated, hollow, refractory tap-hole insert comprising a shell to a clay gun, wherein said tap-hole insert comprises i. a first end and a second end in axial direction, wherein said second end is blocked. ii. an opening arranged on said first end, iii. a hollow passage in axial direction, wherein said hollow passage is accessible through said opening, iv. a plurality of lateral through holes, aligned in a longitudinal direction of the shell, with a constant interval in-between and covering 10-25 % of the shell of the tap-hole insert and arranged in said shell such that said through holes are in fluid communication with said tap-hole channel, i. a first end and a second end in axial direction, wherein said second end is blocked. ii. an opening arranged on said first end, iii. a hollow passage in axial direction, wherein said hollow passage is accessible through said opening, iv. a plurality of lateral through holes, aligned in a longitudinal direction of the shell, with a constant interval in-between and covering 10-25 % of the shell of the tap-hole insert and arranged in said shell such that said through holes are in fluid communication with said tap-hole channel, ∘ inserting said tap-hole insert into said tap-hole channel, wherein said clay gun is fluidly coupled with said tap-hole insert and said tap-hole channel, ∘ injecting a grouting material from said clay gun into said tap-hole insert and through said through hole into said tap-hole channel and, ∘ disconnecting said tap-hole insert from said clay gun.