Meth Residue In The Pipe Stem - A good sign or a bad sign ?

[Chip (OP)]

Neither on its own, because stem residue is a weak signal. It mostly reflects where the vapour condenses, not what's in the product.

Why there can be little residue:

• Meth freebase vaporises cleanly, so a good-quality crystal heated gently mostly goes to vapour and into the lungs, leaving the stem fairly clear. This is the "good" reading.
• A short or warm stem, a wide bore, or hard, steady draws push vapour through to your lungs before it can condense on the glass.
• If you're heating very gently, much of it can also just sit in the bowl and not vaporise fully, so a clean stem doesn't prove you're getting the whole hit.

What to look at instead:

• Colour of what does deposit. A thin white or clear film is normal condensed freebase. Yellow, brown or black residue suggests overheating (decomposition products) or non-volatile cuts and impurities.
• What's left in the bowl. If it vaporises and leaves almost nothing, that points to clean, volatile material. A dark, tarry, or crusty leftover means either too much heat or non-vaporising adulterants.
• Smell and taste. A harsh chemical or plastic note is a worse sign than how much residue there is.

One caveat: some common cuts, like MSM, also vaporise and recondense. So "burns clean and leaves little behind" doesn't rule out dilution. Only a reagent test (Marquis, Simon's, etc.) or a proper analysis tells you that.