At the end of menses there tends to be light brown and blackish discharge.

Do we wait for these to end too before commencing Salah?

Menses end by two signs; a white discharge that appears at the end or dryness, that is, the bleeding stops completely. Thus if any of these signs appear the woman is clean and can pray. Therefore if the brown and blackish discharge appears after cleanliness (tuhr) has occurred then it does not have any effect. However, if it appears before tuhr then it is considered to be part of the menses.

This is what is pointed out by the hadith of Umm Atiyyah: "We used to regard the yellowish or brownish discharge after the tuhr as not being of any significance." [Narrated by al-Bukhaari, 320; Abu Dawood, 307; an-Nasaa’i, 468; Ibn Maajah, 647]

And in connection with seeing a discharge before tuhr the hadith says, from Um Alqamah says, "The women used to send to ‘Aa’ishah the Mother of the Believers small vessels in which there was a cloth on which there was yellowish discharge from menstrual bleeding, asking her about prayer (i.e., whether they could resume praying), and she would say to them: Do not be hasty, until you see the white discharge – referring to the tuhr which signals the end of the period.” [Classed as Sahih by al-Albani in Irwa’ al-Ghaleel, no. 198] Also narrated by al-Bukhari in a muallaq report (Kitaab al-Hayed, Babb Iqbal al-Maheed wa Idbaruhu)