Crystal Palace have promised to ban indefinitely any fans found guilty of throwing missiles at recent home matches.
Newcastle captain Fabricio Coloccini was hit by a coin when celebrating his side's goal during a 1-1 draw at Selhurst Park on 11 February.
An object was also thrown from the crowd during Saturday's 2-1 home defeat by Liverpool in the FA Cup fifth round.
"We take a zero tolerance approach to this sort of behaviour and, if the perpetrators are identified, they will be banned indefinitely from the stadium," said a statement on the club's official website.
"If they are season ticket holders their cards will be made void without a refund.
"The stupid behaviour of a few supporters risks creating a negative image of our club and we would appreciate the help of Palace fans in identifying the culprits, who are not welcome at Selhurst Park."