On 2/23/2012 9:46 AM, Larry Jaques wrote:
> On Thu, 23 Feb 2012 08:18:31 -0500, "Mike Marlow"
> <
mmarlo...@windstream.net> wrote:
>
>> HeyBub wrote:
>>
>>> I recently grabbed an ordinary red shop rag to wipe down a bathtub
>>> with Muriatic acid.
>>>
>>
>> Dude - that's one hell of a cleanliness fetish you have there! Most people
>> would be happy with a quick swipe with a household cleaner to get the ring
>> out.
>>
>>> The rag turned blue! (really an intense purple)
>>>
>>> When the job was finished and I rinsed the rag, it turned back red!
>>>
>>> Do I have a Litmus rag? Just out of curiosity, anybody know what went
>>> on?
>>
>> No clue. But - Pity the person that climbs into that bathtub next...
>
> Yes, shop rags are treated to show you when they've become
> contaminated with acid, usually battery acid. It helps the mechanic
> keep the acid from being passed around to other items. If it turns
> blue, toss it in the laundry bin.