| Using sealants which can discolour as a result of absorbing soil or dirt particles from atmospheric pollutants. |
| Because of its porosity, it tends to absorb grease and oil, which discolour it. |
| Having digital copies is all very well but they don't fade and discolour as the years go by. |
| Once activated, the nickel shield will quickly discolour from exposure to heat. |
| Once the fuzzy grey fungal growth appears on the foliage, causing it to discolour and rapidly deteriorate, the disease may then spread into the main body of the plant. |
| If the ink is placed too near the surface, it will prematurely fade or discolour. |
