If you want to check Meth concentrations on walmart products check this out

Material Safety Data Sheets

you can also see if it contains products other than water and meth.

I found some more windshield washer we can use at K Mart

Here are some pictures of it

http://media6.dropshots.com/photos/5...7/b_200526.jpg

http://media8.dropshots.com/photos/5...7/b_200831.jpg

http://media8.dropshots.com/photos/5...7/b_201044.jpg

Here is the MSDS

http://www.hardwarestore.com/media/msds/256131.pdf

At K Mart I bought splash -30 de-icer premium windshield washer it is.

38% methanol by weight
41% methanol by volume

When I shook it up the bubbles went away quickly. Just water & methanol & a little bit of red die in it.

It was $3.49 per gallon.

Home Depot is currently carrying Winter Warrior De-Icer washer fluid. It's rated at -30 and doesn't stay foamy when shaken. It's made by South Win LTD but they dont have MSDS on their website. Searches suggest 40%ish.

oh wait, found the msds at home depot

Water 50- 70 %
Methanol 30-50 %
Propylene Glycol 1 -5 %

The last item suggests it's a bad idea. I will try to find something else.

OT - thanks for the reminder. I'm pretty sure my folks who are watching over my Miata back in Jax have been filling the reservoir with distilled water, and it does drop below freezing some nights.

What does the shaking and checking for bubbles do?

Check for soap?

Look at the MSDS safety sheet for any juice you want to run in your engine. As Y8s said above, it will state what the actual contents are. Shaking doesn't necessarily tell you what's in there.

FWIW I've been rocking Peak -20 for several months and it works. Yay.

Update to Wal Mart MSDS link:

Wercs UPC/Barcode - Powered By The Wercs

Super Tech 0°F Washer Fluid is commonly available in my area for $1.88/gallon. MSDS says 25% Methanol by weight with no other hazardous components. That equates to ~31% Methanol by volume. Not bad. Think I'll start using it.

FYI:
1 Gallon of Water = 8.35 pounds
1 Gallon of Methanol = 6.6 pounds