It doesn't sound good. Denatured alcohol may contain many things beside methanol. See:Gum Base said:Will this work?
Ethyl alcohol, 30mL
This is denatured ethanol (95% ethanol, 5% methanol).
http://en.wikipedia.org/wiki/Denatured_alcohol
Denatured means "made unfit for human consumption". This is a no-no if you plan to IV because it may contain a chemical that doesn't evaporate and is toxic in very small quantity.
As a solvent for purifying snortable blow it is just possible that methanol alone doesn't interfere because it probably solvates the same stuff as ethanol, but don't take my word for it, I haven't checked on methanol.
Note that if you wash the freebase with, say 95% ethanol + 5% water, the freebase (crack) will dissolve entirely in the ethanol (it is soluble in Vodka which contains much less ethanol!) so at least you can throw away the filtrate without any fear of losing good stuff. But you're stuck again if you want to acidify the freebase into blow because the 5% water will act as a sink for newly-formed Coke-HCl.
By the same token if you dissolve your freebase in 95% ethanol + 5% methanol, all the freebase will be dissolved in the 95% ethanol even if it doesn't dissolve in the 5% methanol. So again any solid residue can be disposed of with a clear conscience : it is something that doesn't dissolve either in ethanol or methanol, ie it is neither blow nor freebase/crack.
If you're dissolving the HCl instead of the freebase, you should apply the quantities mentioned by Le Junk as regards the solubility of blow in ethanol (so many ml ethanol per ml blow). Add 5% solvent for the egregious methanol and subtract 20% (or 30%, or more) according to your hypothesis as to the purity of your material. If you (or someone else on this forum) finds out that methanol has nearly identical solvating properties as ethanol as far as cocaine is concerned, you're in business with your mixture and you can treat it as though it were pure ethanol (keeping in mind though that methanol is poisonous).