The bottle says 30%? Most are 100% tce, but SWIM has came across ones that contain toluene and DCM along with it. Those are usually cheaper than the pure tce, and work fine for most purposes (SWIM has used it before without probs). What does the spray smell like (besides the tce of course)? Does it have an underlying lighter fluid kinda smell? Or is it more of a gasolene smell (the lighter fluid smells point to naptha's in the mix, the gas smell would be toluene/xylenes and shit)? You could always do a google search on it. Just type in the brand name (like John Does Brake Cleaner for example) and type MSDS after it. You may have to do a little digging but I'm sure there is an MSDS on the product that'll give hint to what's in it. Other than that, get a new bottle, a brand that says tce and nothing else. When in doubt, throw it out!