OK, the entrance is still blocked!

Hint 1 of 5:

Use a change potion on the silver bars

Hint 2 of 5:

Use venom on the snakes

Hint 3 of 5:

Use a fire potion on the rubies

Hint 4 of 5:

Put out the fire with water

Hint 5 of 5:

Collect water from Second Garden with the cauldron