The proposed solution includes a fixed 1 msat payment made unconditionally when offering an HTLC and a hold fee paid when receiving an HTLC, which is refunded if the HTLC is settled before the hold grace period ends. The values for the fees are chosen for the simplicity of the example's sake, and calculations will be done to figure out a good value if the proposal works to fight spam. The forward fee is meant to fight uncontrolled spam, while the backward fee is meant to fight controlled spam. The proposal has only a tiny cost for honest senders (the forward fee). The author acknowledges that there may be some griefing attacks or missed types of spam due to the mechanisms introduced and emphasizes that the implementation details can be figured out collectively later.