Clean riddles

What can go up a chimney down but not down a chimney up?

I can be as thin as a picture frame but my insides have many things you can see. What am I?

A petshop owner had a parrot with a sign on its cage that said "Parrot repeats everything it hears". Davey bought the parrot and for two weeks he spoke to it and it didn't say a word. He returned the parrot but the shopkeeper said he never lied about the parrot. How can this be?

I am seen in the water if seen in the sky, I am in the rainbow, A jay's feather, And lapis lazuli.

I look flat, but I am deep, Hidden realms I shelter. Lives I take, but food I offer. At times I am beautiful. I can be calm, angry and turbulent. I have no heart, but offer pleasure as well as death. No man can own me, yet I encompass what all men must have.

What is the easiest way to double your money?

What can be swallowed, but can also swallow you?

In a supermarket, the first 25 customers of the day purchased an average of two items each. After a further 15 customers, the average number of items purchased by each customer rose to eight. What was the average number of items purchased by the last 15 customers only?

When you put this in a heavy wooden box, the box will become lighter.

How many apples can you put in an empty box?