Almost 300 wraps of crack cocaine and heroin were seized by Essex Police after a car was stopped in Colchester.
Officers spotted a Citroen in Grange Road on Monday, February 17.
When they stopped the vehicle, they found about 50 wraps of what appeared to be crack cocaine and heroin, as well as a bottle containing a potentially noxious liquid.
An 18-year-old man was arrested on suspicion of possession with intent to supply Class A drugs and possession of a noxious substance.
Officers then searched an address Colchester, finding between 200 and 300 wraps of Class A drugs.
The teenager, from Romford, was questioned and released under investigation.
Essex Police say the patrols were carried out as part of Operation Sceptre, which tackles serious violent crime and knife crime.
You can report incidents to Essex Police by calling 101, or contact Crimestoppers anonymously on 0800 555 111.
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