(To be demanded of a sponge)
This shows symbolism because sponges in nature sit there and absorb water and food through the current of the water. If the current continues to flow the sponge will be fed and kept well. Hamlet calls Rosencrantz a sponge because he goes around taking in all the information and background stories he can. This sort of acting is that of what a sponge would do, so thats why he called him a sponge.
(Like some ore Among a mineral of metals base)
This shows symbolism through the fact that these minerals were placed in this base metal and cant be removed unless broken down or melted. Gertrude states that hamlet is still in madness and the only way to calm his madness down is to get rid of him. Because his madness is stuck to him like minerals in base metals.
(Not where eats but where he is eatan)
This very symbolic because it expresses how a man used to sit down at his table to eat what has been prepared for him. But instead he is being eaten where he would normally sit down to eat his meals. Death is definitly taken out of this because of how this is worded.