This advertisement from about 1910 shows that the famous conjure perfume Hoyt's came also as a perfumed talcum powder that could be used as a sachet. I'd be very interested to see someone revive this -- I did include a supposed recipe for Hoyt's scent in my Conjure Cookbook!
Nevertheless, my observations about the uses of Hoyt's in traditional hoodoo lead me to think it may have originally been used as a replacement for urine in spells -- which is to say a powder would make that impractical. Almost all of the old hoodoo spells I've seen that call for Hoyt's cologne, I've seen variants on that used urine in the same place (or sometimes both Hoyt's and urine get used together.) I can say as a professional hoodoo practitioner that this trick of using the Hoyt's instead has sometimes made my job easier when doing work for clients (I'm not going to ask people to send me bottles of their pee to work with. No.)
So if peeing on your mojo grosses you out, douse it in Hoyt's instead. If bathing in your own urine seems nasty, use Hoyt's instead. If you can't bring yourself to keep a bottle of old urine around for your bottle spells, try a bottle of Hoyt's instead.While there's some well known confusion over the name of Hoyt's Cologne (rendered mistakenly Heart's Cologne by Hyatt in his Hoodoo-Conjuration-Witchcraft collection) it seems there was a period when more than one Hoyt's might have been used: