The plastic is very thin. It stains if the contents are anything but plain water. Soaking in warm/hot water will remove most or all of the stain - but it will stain again.These bottles are exactly what I wanted as far as size, price and "squeezability." But be aware of what you're getting (cheap, cheap, cheap).
ULAB Scientific 1000Ml Borosilicate Glass Beaker With Printed Graduation - Durable And Accurate For Lab Use (UBG1005)
12 Review
4 Oz. Amber Boston Round Glass Bottles With Black Dropper - Pack Of 24
11 Review
Get Your All-Purpose Cleaning Solution With Bealee'S 24 Oz Plastic Spray Bottles - 2 Pack
16 Review
Graduated Erlenmeyer Glass Flask Set With Narrow Mouth - 500Ml Capacity
15 Review