If Wright's stain is too dark, it is difficult to distinguish between satellites and silver staining on NOR's. It is a clear solution initially, thus difficult to detect. If allowed to get on skin, it can cause a chemical burn which turns black. This can not be washed off. Discoloration disappears only when a new layer of skin is formed.
Clothing is also vulnerable to silver-nitrate staining.
Slides that have been previously G-banded are not suitable for NOR staining. C An improved technique for selective silver staining of Nucleolar Organizer Regions in human chromosomes.