Here's why and some other options:
* Methylene Blue: This is a readily available and effective stain. It's a basic dye that stains acidic (negatively charged) structures like DNA and RNA, making the nucleus and other cellular components more visible.
* Iodine: While used in Gram staining of bacteria, iodine can also be used to stain cheek cells. It will stain the starch inside the cheek cells.
* Crystal Violet: Another basic dye similar to methylene blue, and can be used for cheek cells.
* Safranin: This is another basic dye that can be used.
* Giemsa stain: A Romanowsky stain commonly used in cytogenetics and histology, this can also be used to stain cheek cells, revealing nuclear details.
The choice of stain depends on what you want to visualize and the resources you have available. For a simple and effective stain to see the nucleus, methylene blue is usually the best choice for cheek cells.