South Wales Police say anyone caught spraying or writing graffiti "will be dealt with efficiently and appropriately".
Over the last two or three months, the tag SPEC has been sprayed on property across Ely and Canton.
This was a concern to the community and we are glad that the person responsible has apologised and agreed to clean up the damage.
Graffiti is criminal damage, which can affect quality of life, increase fear of crime in some areas and reduce pride in a community. This will not be tolerated.
More top news
Charities in Wales say thousands of low-income families with disabled children could be missing out on grants, because of government cuts.
Tuesday will have a murky start with widespread fog, mist and low cloud.
A plan to secure the future of Port Talbot steelworks will be unveiled to staff on Wednesday, ITV News understands.