In addition to the fishskin and the tight braids, I have read that Dietrich employed another old fashioned beauty trick (which was probably well known to 19thc society ladies), namely that of wearing a fine gold chain, drawn tightly under her chin to give her neck a better line.
MF and Alexandra did age well, it has to be said. Even in an age of rigid corsetry, they retained their figures and some of their looks. Some of the photos from the 1900's of Alexandra, notably the Coronation portraits, are very heavily retouched, mainly around the eyes. Alexandra was obliged (as was May of Teck) to employ a little extra artifice in the hair department, wearing what was known discreetly as a "transformation" - namely a hairpiece, which was frizzed and sat on the front of her coiffure and thus gave her enough hair for the fashionable hairstyles.
If memory serves me, this "transformation" came in useful when an attempt was made on Bertie's life at a railway station; the bullet apparently lodged itself in Alexandra's hairpiece!
On the subject of the fishskins - we still use them in the theatre world. My most recent experience was our Wigs Mistress having to obtain them for a soprano (who was 56) who was singing Aida with us and needed to look 20! Needless to say, there weren't enough fish in the sea to effect that particular miracle!
