Any tips on rooting and growing from an avocado seed?

My grandchildren have had great success by first washing the seed with water,
then wrapping the seed in a moist paper towel and putting it all into a
zip-lock plastic sandwich bag. The bag is then placed on top the refrigerator
where it is warm. When they see roots coming thru the paper toweling, they
carefully remove the toweling and plant the seed in a pot. We have had several
nice-sized foliage plants from this process.
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