Sections should appear clear after the deparaffinization step. If white patches are present, this in an indication that the slides were not completely dried and/or deparaffinized.
- Insufficient drying time
- Insufficient time in xylene
- Return the slides to the oven or place them in 100% alcohol
- 2-3 changes of xylene over a period of 10 minutes should be sufficient time to remove all of the paraffin