I work in the perfume industry and as I travel a lot in Africa I’ve been interested in this for years.
DEET is the most effective mossie or midge repellant but after you’ve applied it, it comes out in your urine for 48 hours as it’s readily absorbed. You can get DEET in various bases including creams or lotions or petroleum jelly or gels and what matters is the dosage, not the brand. It does damage certain plastics so keep it away from glasses and so on.
Skin so Soft contains a strong powdery green fougere perfume not unrelated to Brut, and having used it while fixing punctures in the woods I know it works. The study linked above shows it to be almost as effective as DEET. The Avon product is called a dry oil simply because it’s not wet, i.e. water-based. It’s just a grade of mineral oil that’s light enough to be fairly volatile. There may be a couple of percent of citronella oil or the molecule citronellal in that green fougere perfume but the dosage on the skin is very low as the perfume itself is only at about 1% in the oil. Citronella oil does repel insects but is so volatile that it will flash off your skin in half an hour. There isn’t anything else in the perfume that’s naturally repellent so my best guess is that it actually masks the odour of the body that insects use to detect that vital blood by smelling very similar to their environment – fougere is fern in French and the perfume does have that strong green ferny smell, so that when you wear Skin so Soft it surrounds you in a heavy aura of perfume and I think it’s this that confuses the insects. It’s an interesting story and our office Avon rep tells me that Avon would love to drop that old-fashioned perfume but can’t because it’s their best seller.