Well, if this thread is still here I am assume this isn't against the TOS?
Ripped from some shady corner of the internet.
1) Dissolve the cocaine HCL in some water, add some decolorizing carbon and filter.
2) Add 28% aqua ammonia to the solution obtained in step 1 to produce the cocaine freebase and extract the freebase with low boiling petroleum ether.
3) Allow the petroleum ether to evaporate, dissolve the freebase in acteone and, if cloudy, filter again.
4)Prepare a solution of 1:2 conc. HCL in methanol. Use the aqueous HCL/methanol to acidify some acetone and then add to this solution the cocaine freebase/acetone solution.
5) Stir and allow the cocaine HCL to crystallize. Filter and acetone wash.
TO SUMMARIZE:
If any of the concepts are foreign to you (i.e. performing a chemical wash, an extraction or a filter), consider not attempting this.
Also, remember that petroleum ether has wonderful potential as a scarring tool, thanks to explosivity.
Finally, remember the bible:
http://www.amazon.com/exec/obidos/ASIN/0471129488/qid=1021195868/sr=8-2/ref=sr_8_3_2/002-7711694-8325665