How can one dispose of money earned from work that may involve impermissible (haram) elements, taking into account currency fluctuations and varying payment receipt times, and do previous donations count as expiation?

The earnings from publishing clips that contain music or articles that contain pictures of women are not absolutely forbidden. The ruling depends on the original intent of the material. If it is permissible and beneficial, then taking payment is allowed, because the music and pictures are secondary, and "what is tolerated in secondary matters is not tolerated in primary ones."

Accordingly, the aforementioned earnings are not forbidden unless the original intent of the published material was forbidden. Disposing of this amount should be done with the currency the questioner received.

As for the previous donation from the money, since charity is only accepted from lawful money, as "Allah is good and accepts only what is good," the questioner's donation did not suffice to purify the money. Disposing of unlawful money requires the intention of getting rid of the unlawful, and charity does not suffice for purifying the money.