(1) The required notices shall be given in writing. The notice of intent to forfeit shall be signed by the seller or by the seller's agent or attorney. The declaration of forfeiture shall be signed and sworn to by the seller. The seller may execute the declaration of forfeiture through an agent under a power of attorney which is of record at the time the declaration of forfeiture is recorded, but in so doing the seller shall be subject to liability under RCW 61.30.150 to the same extent as if the seller had personally signed and sworn to the declaration.

(2) The required notices shall be given:

(a) In any manner provided in the contract or other agreement with the seller; and

(b) By either personal service in the manner required for civil actions in any county in which any of the property is located or by mailing a copy to the person for whom it is intended, postage prepaid, by certified or registered mail with return receipt requested and by regular first-class mail, addressed to the person at the person's address last known to the seller or the seller's agent or attorney giving the notice. For the purposes of this subsection, the seller or the seller's agent or attorney giving the notice may rely upon the address stated in any recorded document which entitles a person to receive the required notices unless the seller or the seller's agent or attorney giving the notice knows such address to be incorrect.

If the address or identity of a person for whom the required notices are intended is not known to or reasonably discoverable at the time the notice is given by the seller or the seller's agent or attorney giving the notice, the required notices shall be given to such person by posting a copy in a conspicuous place on the property and publishing a copy thereof. The notice shall be directed to the attention of all persons for whom the notice is intended, including the names of the persons, if so known or reasonably discoverable. The publication shall be made in a newspaper approved pursuant to RCW 65.16.040 and published in each county in which any of the property is located or, if no approved newspaper is published in the county, in an adjoining county, and if no approved newspaper is published in the county or adjoining county, then in an approved newspaper published in the capital of the state. The notice of intent to forfeit shall be published once a week for two consecutive weeks. The declaration of forfeiture shall be published once.