You're probably talking about speed that you buy in paste form on the street, mainly in Europe. read more
This is not methamphetamine, but racemic amphetamine sulphate (benzedrine), it's sold wet because the 'cook' (somebody who throws amphetamine oil together with methanol and then adds sulphuric acid till it reaches a PH of 6,7 and leaves it alone for a day and night. read more
Amphetamine at excessive dosage can cause some damage by downregulating receptors (they are reabsorbed from the surface of neurons), meaning you need more stimulation to feel really alive and triggering a slide into addiction. read more
If it's amphetamine hydrochloride, it has a tendancy to absorb moisture from the atmosphere - enough to make it perm. damp, but I don't think that's what's in 'base' as amphetamine hydrochloride is soluble in ethanol & isopropanol, but if you wash 'base' with isopropanol, it doesn't just dissolve in the alcohol. read more