Empty Caulk Tube - FILLABLE CAULKING Cartridge - Lowest Price - 8 Pack - Made in USA

Q: What is the melting point of these tubes?

They are made of HDPE plastic which has a melting point of 239–275 °F

Q: The title states 8 tubes. More about this item states "The package include 4 plastic caulking tubes each with plunger cap". So how many, 8 or 4 ?

It is 8 tubes. Thanks for finding the error in the listing. I have updated the bullet point to say 8 tubes.

Q: can these be reused again?

I reused the same tube 4 times in one day when grouting my tile with a two part epoxy grout. I used a new tube the next day because I could not wash out the epoxy. On a different job I used it for cement grout and washed it easily after each use. The challenge I have with them is filling the tube once I have a custom mix in a bucket that is curing quickly.