I accidentally used meat wooden spoon while cooking a parve dish in a milk pot, and then washing the spoon with a milk sponge. Do I need to replace the spoon?
No you don’t have to replace the spoon, unless you know specifically that the pot was used to cook hot dairy within the 24 hours before the spoon was put into the pot. Usually we assume that it wasn’t and therefore the spoon is not milky from the pot. Regarding washing the spoon with a milky sponge, since the sponge only has a minimal amount of actual milk on it, coupled with the fact that the water from the faucet is only iruy kli rishon, therefore the spoon does not have to be kashered.