Reward points are primarily Acid Mines way of thanking the player for taking the time to vote for them. As such they are gained largely by the player Voting regularly. That said, players may also gain reward points from other sources such as magic books which can be gained from the treasure hunt.
Reward points can be redeemed for merchandise at the Rewards Shop.
Reward points do not expire so there is no time limit for their use which allows players to accumulate points over time to gainI think more "expensive" items.
To visit the Rewards Shop a player should type /rewards shop in the chat display.
To check their rewards points tally a player should type /rewards in the chat display.