# Laundry-related question: What is/was a "blue bag"? **URL:** \ **Category:** Factual Questions\ **Created:** [October 21, 2005, 6:08am UTC](https://boards.straightdope.com/t/laundry-related-question-what-is-was-a-blue-bag/327225 "2005-10-21T06:08:54Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Cunctator](https://avatars.discourse-cdn.com/v4/letter/c/43a26b/32.png) [@Cunctator](https://boards.straightdope.com/u/Cunctator)\ **Post date:** [October 21, 2005, 6:08am UTC](https://boards.straightdope.com/t/laundry-related-question-what-is-was-a-blue-bag/327225/1 "2005-10-21T06:08:54Z")
In yesterday’s lecture for my Intellectual Property Law course we covered the tort of passing off. One of the cases (which I think was English - I don’t have the actual cite with me) was from the 1930s and dealt with rival manufacturers of laundry “blue bags”. It was unclear from the case extract in the text book exactly what the function of these blue bags was. The notes in the text book weren’t especially helpful either. They simply said “if you don’t know what a blue bag was, ask your grandmother”. Can anybody enlighten me? ---
**Author:** ![TheLoadedDog](https://avatars.discourse-cdn.com/v4/letter/t/35a633/32.png) [@TheLoadedDog](https://boards.straightdope.com/u/TheLoadedDog)\ **Post date:** [October 21, 2005, 6:28am UTC](https://boards.straightdope.com/t/laundry-related-question-what-is-was-a-blue-bag/327225/2 "2005-10-21T06:28:16Z")
As far as I know (remember my mum talking about _Reckitt’s Blue_), it was a fabric whitener that came in little bags. [Photo](http://www.trademe.co.nz/Antiques-collectables/New-Zealand-Maori/auction_photo-37444138/permanent-0/photoid-13719125/p-1/m-0187%2D0449%2D/title-Wash+Day%22+KIWIANA+%22+Reckitt%27s+Bag+Blue.htm) ---
**Author:** ![Rayne\_Man](https://avatars.discourse-cdn.com/v4/letter/r/df705f/32.png) [@Rayne\_Man](https://boards.straightdope.com/u/Rayne_Man)\ **Post date:** [October 21, 2005, 6:34am UTC](https://boards.straightdope.com/t/laundry-related-question-what-is-was-a-blue-bag/327225/3 "2005-10-21T06:34:28Z")
The blue bag contained a powder that was supposed to make the clothes look whiter , I think by adding a slight blue colour to them . I know it sounds a bit strange, but I think it is to do with ultra-violet light. I am sure a similar thing is a component of modern detergents. I have found mention ( and a picture) of a blue bag here:- [Victorian washdays](http://www.elmbridge-online.co.uk/themagazine/washday.asp) ---
**Author:** ![Cunctator](https://avatars.discourse-cdn.com/v4/letter/c/43a26b/32.png) [@Cunctator](https://boards.straightdope.com/u/Cunctator)\ **Post date:** [October 21, 2005, 6:46am UTC](https://boards.straightdope.com/t/laundry-related-question-what-is-was-a-blue-bag/327225/4 "2005-10-21T06:46:50Z")
Thanks \*\*TLD \*\* and **Rayne Man**. I note that both of your links were to the \*Reckitt’s \* version and that actually rings a bell with my childhood memories too. Of course, in the meantime I’ve had a return call from my mother and she confirmed that it was a fabric whitening agent and that \*Reckitt’s \* was the most popular brand in Australia (and probably New Zealand too judging by \*\*TLD’s \*\* link). ---
**Author:** ![Beware\_of\_Doug](https://avatars.discourse-cdn.com/v4/letter/b/278dde/32.png) [@Beware\_of\_Doug](https://boards.straightdope.com/u/Beware_of_Doug)\ **Post date:** [October 21, 2005, 6:49am UTC](https://boards.straightdope.com/t/laundry-related-question-what-is-was-a-blue-bag/327225/5 "2005-10-21T06:49:55Z")
> [@Rayne Man](#): > > The blue bag contained a powder that was supposed to make the clothes look whiter , I think by adding a slight blue colour to them . Exactly. It’s still sold, usually in bottled form, where it’s called [bluing](http://www.walco-linck.com/bluette.html). ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [October 21, 2005, 7:56am UTC](https://boards.straightdope.com/t/laundry-related-question-what-is-was-a-blue-bag/327225/6 "2005-10-21T07:56:25Z")
Many laundry detergents use optical brighteners (that fluoresce blue under UV) today for the same reason. ---
**Author:** ![Beware\_of\_Doug](https://avatars.discourse-cdn.com/v4/letter/b/278dde/32.png) [@Beware\_of\_Doug](https://boards.straightdope.com/u/Beware_of_Doug)\ **Post date:** [October 21, 2005, 2:02pm UTC](https://boards.straightdope.com/t/laundry-related-question-what-is-was-a-blue-bag/327225/7 "2005-10-21T14:02:59Z")
> [@TheLoadedDog](#): > > (remember my mum talking about _Reckitt’s Blue_) Reckitt? Nearly killed it… 😃