Hundreds of diners and pub-goers have been offered compensation for dry-clean only clothing that may have come into contact with the nerve agent used to attack Sergei Skripal and his daughter.
Health officials waited a week after the March 4 attack to issue "precautionary advice" to Salisbury residents after traces of the substance were found in The Mill pub and the nearby Zizzi restaurant.
Up to 500 people who may have visited the venues between the Sunday Mr Skripal, 66, and his 33-year-old daughter, Yulia, were poisoned and when they were closed the following night were told to wash the clothes they were wearing and wipe down other items they handled.
Those effected were advised to put dry-clean only clothing inside two plastic bags and securely tie them at the top.
Almost three weeks on from the original incident, and 12 days after the previous advice was issued, Public Health England (PHE) said those with double-bagged items should contact Wiltshire Council to have them collected.
The update, issued on PHE's website on Friday evening, said the deadline to request collection by letter or email is April 15 and stated: "You will be compensated for any items collected."
Jenny Harries, PHE deputy medical director said: "The risk to the general public from this incident remains low and this has not changed.
"The public's safety is our number one priority and we have adopted a precautionary approach to those who were in the pub or restaurant within the specified time frame.
"We advise that anyone who was wearing clothes that are dry-clean only should continue to store them safely in two plastic bags, securely tied at the top until collection.
"They will now be able to contact the council using the specified details to arrange safe collection of these items."