Instruction: Generate an answer to the question by utilizing the information contained in the document.

Input:
Question: Do these bottles leak? Most I've used leak from the threads not sealing completely.
Document: So, I wrap regular plumber's tape ( teflon sealing tape ) around the threads. Works beautifully!Another application I use these for is dispensing controlled amounts of very thin shellac. The tape-trick fixes that problem too! No spills or leaks whatsoever.Taping the threads with teflon tape is cheap, fast and solves two of those problems.No cap? No problem!I use regular stick-pins like those used on office cork-boards & maps.
I really like the bottles but eventually the bottle does begin to leak out from under the lid. This is the best bottle I've found to put my homemade chocolate syrup in. I don't regret the purchase but it would be nice to not have the leak.
All 3 leak at the threads. Complete junk. Maybe if you were filling them with a really thick substance they might be okay, but for anything liquid, forget about it.
I've used these for sauces, homemade condiments, and crafts and they work perfectly for all of these uses. Very easy to clean and manage. Only wish I had thought to buy these earlier! Bon Appetit says they're a must for home chefs.
an efficient squeeze bottle. does not leak when squeezed. very versatile, can be used  for thin  to thick liquid and easy  to clean
It wasn't clear from the photo that the bottles were missing the usual piece that closes off the top and prevents spillage.These bottles are completely useless.
These seemed to work ok for me until one day I dropped one of the bottles. It completely cracked all up. I was surprised that it broke like that because usually plastic is more durable than that.
Nice squirt bottles. They keep liquids and things and don't leak. Squirt well and are useful for cooking. Good deal!
If you use a runny liquid (such as vinegar, water, oil) in these bottles, it will leak out of the twist cap.Don't squeeze the bottle and you should be fine
If you use these bottles for oils or soy sauce and squeeze at high pressure, it will leak out through the cap and becomes very messy. You'll pretty much have to dribble it out with the lightest squeeze.
Answer: Yes they do :(