Those look to be Low Density Poly Ethylene if i had to guess which type of Poly Ethylene since High Density PE is well not as easy to squeezeSo are Fastechs Poly Ethylene(PE) safe for reuse?
$2.35 Empty Dropper Bottles for E-liquids (5-Pack / 30mL) 5-pack - long tip / PE at FastTech - Worldwide Free Shipping
They don't have any recycling symbol.