i took pine cones & dried them on a radiator till they spread out then picked them apart - they can be labelled as dried troll teeth or nails.
picked all the thorns off my roses (yeah i got pricked a few times!) & have Rose thorns in a jar.
take the inside of a highlighter pen out & soak in water - the flourescent colours make great potion spell colours.
Sugar puffs - witches warts
cigarette ash - Vampire ashes
i asked my local keysmith for the filings from the key cutting machine - filled a bottle & labelled Witches Ashes burned at the stake
i used a large bottle and squeezed a plastic skeleton in then filled it with water - shrinking potion
sequins - mermaid scales
green cobweb wisps - frogs breath
I have loads more can't remember them all now

i have pics of some on my albums.