Rowan's store now seems to accept things for sale, that given the nature of his store seems unintentional.
Various things that are generally sellable only to toyfolly or the late jebedezra jeckyls can be sold to Rowan for the prices offered by the latter. PM me for details.
Also on the subject of Rowan's miscellanea items for purchase via Persuade check:
He sometimes sells bundles of potion bottles that are not usable/actual trash:
(https://i.imgur.com/C9H5N7o.png)
(For the record, I've also purchased bundles that are usable and spawn the bottles correctly; it seems to be a toss-up.)