Help! new dress from charity shop stinking of B.O. which won't wash out

[alltoomuchrightnow]

Got stunning dress, it looks completely new (and is a modern dress... I've seen similar in the normal shops)
Got it home..this is not the case (being new). The pits stink of BO. It says to wash it cold with detergent. I didn't have time to faff around so machine washed it on 30, cold. Still smelt. Re machine washed on 30 delicates (warm). Still smells, now of BO and fabric conditioner. The offending areas are stretchy polyester (lycra type). It also has mesh black panel.
What breaks down sweat in fabric but is still kind to fabric?

'Proper' borax is brilliant for this. Polyester and the like holds onto smells. You can buy it from ebay, just made a solution in water and soak the arm pit part in it for half an hour before washing the dress again

White vinegar in rinse cycle.

Sprinkle with bicarbonate of soda and leave for a day. Add brown dettol to the powder or liquid when you re wash it. Hang it in the fresh air to dry and if it still smells sprinkle pure tea tree on it, but be careful oil could mark it. A steam clean might help too?

Use Shout spray - works well on work shirts.

Disinfectant in the wash is another idea - you can get Dettol powder that is specially formulated for this.

Scrub the offending area with a paste made from bicarbonate and water. Soak for a bit in bicarbonate and water and then wash as usual.

Soak in napisan before washing.

I agree you should spray with Shout and soak - then wash again.

Napisan fades so don't use if a coloured dress.

Lol, this thread reminds me of the Seinfeld episode where a parking attendant with really bad BO parked Jerry's BMW and he couldn't get the smell out. He ended up throwing the keys away in a dodgy area but even the thief ran away and wouldn't steal it.

Sorry, derail.
OP, you could use the vanish oxygen hygiene powder and soak the dress for as long as it says on the jar. Unfortunately the dress is probably in the charity shop for this reason.

I got some 'borax substitute' (yeh that's what it's called on box! couldnt get borax and need to sort this out quick) and about to give it a go! but i do have bicarb of soda in the house so maybe should have just stuck to that. will let you know how it goes and thanks for the suggestions!