This is a video of removal of permanent marker markings on quartz tubes with a halogen point heater.
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Related page:
Heating of the refractory brick 
Heating of the tile 
No.4 Joint of thermoplastic resin tubes 
No.1 Cold air cooling of test tubes 
No.10 Removal of the surface tension of the pipe hole drilling 
Heat dissolution of black lava 
Heating, melting and vitrification of rocks series 28 – Snowflake obsidian 
Heating, melting and vitrification of rocks series 23 – Sandstones