No demurrage on seized goods: production of a proper officer certificate prevents rent charges and requires compliance. Regulation 6(1)(l) prohibits Customs Cargo Service Providers, including Container Freight Station custodians, from charging rent or demurrage on goods seized, detained, or confiscated by the proper officer. CCSPs must allow release on production of a certificate from the proper officer certifying the detention period and must not charge or collect any rent or demurrage for that certified period. Non compliance attracts penal action under the Regulations.