Even if you successfully complete the extraction, your powder will look like yellow dog snort because of the Guaifenesin. Now, like the other gentleman said, get a cough syrup without Guaifenesin. You said it's not an option ATM, well in that case all you're left with is to throw that shit down the toilet because you ain't getting anything out of it.
Get something without Guaifenesin. End of story.