Start Here: What 3D Clean Is and When to Use It – 3D-Fuel

3D Clean is a purge compound in filament form. You run it through your hotend to push out leftover plastic, colorant, and debris before you print with something new. We've made it in Fargo for more than a decade, co-developed with Dyna-Purge, the company that makes the purge compound we use on our own filament extruders.

How it works

3D Clean blends polymers of different densities, which gives it a soft scrubbing action. It expands slightly in the hotend so it fills the space and grabs what's stuck to the walls, then carries it out through the nozzle tip.

Not foaming. It expands a little, but it doesn't foam.
Not abrasive. There are no glass fibers in it, so it won't wear your nozzle.
Not chemical. It cleans mechanically, by flowing through and scrubbing.

The 5 essentials

Heat to the hotter material. Purge at the temperature of the material you're removing, or 230°C, whichever is higher.
Purge between material changes. That's what 3D Clean is for. See Switching materials.
Keep going until it runs clean. Stop when the output is translucent and milky, with no old color or black specks.
It needs somewhere to flow. 3D Clean can't clear a nozzle that's completely blocked. See When nothing comes out.
It's a purge, not a cold-pull material. See 3D Clean and cold pulls.

Where to go next

Prefer video? John explains 3D Clean in this interview on Where Nerdy is Cool!