Sometimes, a bedikah cloth or a stained garment must be brought to a halachic authority to determine whether it is problematic. (Brown, black, pink, or orange stains generally require a question.) It is to a woman's benefit to ask a question rather than just "wait another day or two".This is particularly true in cases where one is trying to conceive.
The cloth or garment with the stain should first be left to dry undisturbed in a clean place and then placed into a clean plastic bag or envelope.
You may bring the cloth or garment to a rabbi yourself, or you can ask your husband, the rabbi's wife, or a yoetzet halacha to serve as an intermediary. You may even place the cloth in an envelope with a covering note and leave it in the rabbi's mailbox, provided you are certain he will receive it promptly. Women in locations where no rabbi is available can make arrangements to send cloths by overnight mail or delivery services. Questions that do not involve stains or bedikah cloths may also be asked over the phone.
In order to give an accurate ruling, the halachic authority should have the following information (if you are not asking the question in person, include a note):
1) Your name (optional) and phone number, email, or other way to contact you (mandatory). The process can be done anonymously without giving your name. You can even leave an assumed name with your phone number, as long as anyone who might answer the phone will know to call you to the phone.
3) For a stain – at what point in your cycle did it occur (before or after mikveh immersion, during the seven blood-free days, on a day of anticipated menses)? Did you feel a hargashah before discovering the stain? Do you know of any plausible alternative source for the stain?
6) Any other information you think might be relevant.
Whenever possible, the actual stain or bedikah cloth should be brought to the halachic authority for evaluation. When a woman does not have access to a halachic authority, we recommend Tahor App, which uses sophisiticated color calibration technology to allow women to send accurate photographs for rabbinic evaluation. Tahor is currently available for iPhones and for a few models of Android phones.