There is a thread dedicated to this in the amphetamines section.
Contrary to the method posted, I have found dissolving your powder in boiling hot water until there are NO solids and then adding sulphuric acid conc. as fast as I can (CAREFULLY IN A SUITABLY BIG VESSEL) while also avoiding excessive splashing.I keep adding until there is no increase if the organic layer which will float to the top instantly.Stirring is applied for a bit and is left to settle, extracted with whatever non polar there is on hand and separated in sep. funnel.Remaining water layer gets extracted with solvent again, fractions pooled, washed with water and brine afew times each then dried over MgSO4. You can steamdistill this if you want or evaporate solvent for storage as is.
The method posted is also good, will enjoy higher yields if you reflux a bit after.I do recommend sulphuric however, as opposed to HCl.