YT2095 - 8-7-2006 at 02:54
I`ve ruined my best pair of levis, it would seem that I sat on some FeSO4.7H2O crystals that accidently spilled onto my chair.
needless to say after being washed there are Many bad rust stains and a few holes also 
Not wishing to generate More holes, can anyone suggest a suitable reactant to get rid of these unsighly patches?
I`m considering Oxalic acid...
your input would be appreciated as my wife is all but ready to kill me!
Nerro - 8-7-2006 at 06:23
I would recommend against using oxalic acid to wash your pants. I believe oxalic would create some yellow precipitate with Fe 2+ and 3+. Also washing
clothes with acids may not be a great idea.
Just sneak out and buy new pants quickly 
Mr. Wizard - 8-7-2006 at 06:39
Maybe you can start a new fashion trend You could also get some more of the
FeSO4.7H2O and evenly stain your pants to make them the same color. I think your options are to chance removing the stain with Oxalic Acid, Sulfamic
Acid or using a commercial rust remover such as Naval Jelly which contains a mix of acids. You might try vinegar or lemon juice first. Test it on an
inconspicuous spot first. Or you might get more ideas from Google: "rust stains from clothes"
12AX7 - 8-7-2006 at 08:03
I've got some stains on several pairs of pants, too. I thought of that, staining them fully! 
I was thinking of using half strength muriatic acid, although that seems a little hard on the cotton. Meh, it's going to be better than sulfuric acid
or copper ions.
Tim
YT2095 - 8-7-2006 at 08:25
I can`t just wear them as is, a few of the stains as positioned such that it would look like I`ve shat myself!
Holes I can live with, Poo(ish) stains... NADA!
metal <--> metal displacement reactions (incl Thermit!) are out the question too.
I can`t go out and buy new, as she already knows about it, and doing the same to the rest would just make more holes, besides I hate the color brown
(as a clothing item).
perhaps I should replicate this again on some junk denim and experiment on that?
I considered it, but have no way of knowing it was that Exact incident that did it or maybe something else???
what I DON`T want is anything that will act as a mordant or color fastener!
DeAdFX - 8-7-2006 at 08:36
well you could use a dilute solution of sodium hydroxide... NaOH + FeSO4 ---> Na2SO4 + Fe2O3
Oxalic acid is great for removing stains. I find it best for removing manganeese stains on my glassware. Anywho good luck.
[Edited on 8-7-2006 by DeAdFX]
Swany - 8-7-2006 at 08:43
The rust is still there, though. You could perpetually reduce your stain to an
iron I salt, such that the stain is now fairly colorless...
But seriously, if you use oxidising agents, you will probably just bleach the spot, no? I don't know how much this matters to you. Reduction or
washing with a suitable, dilute acid to make soluable salts seems like the best option. Hell, I don't really know if that is an option; more like
desperation.
Rather than take guesses on what will work, yeah, I would use expirimental patches of denim to see what goes well, and what would dissolve your pants
to form dehydrated piles of former pants, now carbon.
garage chemist - 8-7-2006 at 08:47
You should try oxalic acid. It's not so strong that it would damage the fabric. After all, it occurs in plants.
Just neutralize afterwards.
A very dilute solution of HF (1-2%) is also said to be very effective at removing rust stains. You could try an acidified solution of sodium fluoride,
though I don't know if it would attack fabric. Perhaps try it with an old pair of pants.
It is interesting that the dreaded skin toxicity of HF is very much diminished in concentrations of less than 5%. Of course, you still have to wear
gloves and be careful.
YT2095 - 8-7-2006 at 09:06
WOOT! 
I got tired of the Guilt Trip(s) so I did it anyway, figured I couldn`t make things any worse (unwearable is unwearable afterall). it Frakin works! in
seconds they just vanish!
and so, they are now in the washing machine (only for a rinse and then dry) and we shall know the FULL results a little later, but for Now, all looks
encouraging 
hehehehe not only that, but now I have a Valid reason to justify my Chem purchases in future 
Nerro - 8-7-2006 at 11:17
I should have known about the oxalic thing sooner, a while back I've cleaned FeSO4 stains out of my carpet using HCl 10%. That can't have been good...
Adar - 8-7-2006 at 12:00
Nice to hear about the stain removal but I think it would have been cooler to do the thermite and post a video .
YT2095 - 9-7-2006 at 00:17
well they`re all dry now and not a mark in sight, as for the holes I`ll probably just go around them with Cyanoacrylate to prevent them getting bigger
(or at least buy some time).
BTW, they weren`t actualy washed in the Oxalic acid soln, I simply put half a gram in a small bolw added a little water enough to dissolve it, and
then dabbed it on the stains with a sponge, they vanish righ before your eyes, and stay gone after being washed (rinse cycle on the washing machine).
I`ll probably experiment a little later on with different metalic stains and see if it`ll work on them too, I might even be able to breathe new life
into my old LabCoat
IrC - 9-7-2006 at 17:20
Commercial laundry places use a yellow bottle called "erusticator" IIRC. After seeing on the label that it was nothing more than a 2 percent HF
solution I snagged a bottle and used it for many years whenver I wanted to make a frost on glass, which it did very well. That was back in the 70's
and I had no internet to learn about such things, never knew how dangerous HF was as I played around with that stuff with never a thought of getting
it on my skin or breathing the fumes. The damn warning label was useless at best, IIRC it said something or other along the lines of "uh, gee, don't
drink this or anything"!
Nerro - 10-7-2006 at 01:10
Just curious, now that the intent of this thread has been satisfied anyway.
Could tartaric acid be used to similar or even greater effect? It would seem like and even better complex former than oxalic acid. As a matter of fact
I'm going to stain a bit of cloth with some FeSO4 right now and find out
woelen - 11-7-2006 at 01:52
Another very good complexing agent for iron is dilute phosphoric acid. I tried this. It makes colorless solutions of iron (III). Also quite
interesting to see that a strongly colored iron (III) solution becomes colorless on addition of phosphoric acid.
My experience with oxalic acid as rust remover also is very good. I had a big brown spot in a white hard plastic sink, which could not be removed
anymore with whatever kind of soap. I then covered it with a thin layer of oxalic acid and wetted it thoroughly. A few hours later the water/oxalic
acid mix was light yellow. With some water, I could simply rinse all away and the brown spot was gone.
YT2095 - 11-7-2006 at 10:08
Ahhh Yes! Phosphoric, I have some of that but I never gave it a moments thought, it`s also alot less Toxic too
Mumbles - 11-7-2006 at 18:09
Too much oxalic acid may actually work a bit too well. It is sold as wood bleach afterall, and wood is primarily cellulose. Too much and you could
very well bleach your clothes. I have found out from experience that it is certainly possible to bleach fibers with it. The container I had just
bought decided to spill all over the floor in the backseat of my car. I didn't see some underneath some papers (my car is very messy), and voila big
pinkish splotches all over one of the floor mats. Granted, this was after days with pure oxalic acid sitting on it. I may have to give the oxalic
acid idea a try on a few chemically stained t-shirts. I have one with some beautiful MnO2 stains I will give a shot at.