It isn't necessarily a good idea to let "everyone" you run across know more than necessary.
One local thrift shop near me, where I USED to go to get pewter no longer has any it seems. The prick who is married to the owner was in the shop when I was describing to the owner & a clerk why it was I was usually coming in each week and only looking for certain items.
When I told them about my looking for pewter items they said they would call me if any came in. Well after a couple weeks of not hearing anything at all, I stopped in again to check & also to ask them if they had not called due to nothing being in the shop.
The owner was away, but the clerk said to me that once the prick husband heard what I told them about the pewter, he made sure that HE got the chance to get the pewter before I did, so he could melt it & sell it to his Rendezvous attending buddies for melting into their cast muzzle loader balls/boolits. Thus spoiling something which had been a good thing, but once again, the "No good turn goes unpunished" saying came into play, & I lost out by explaining what I was using the pewter for.
So please keep that in consideration when looking out for casting materials.
" The walls have ears!".