Police searching a man from Spalding found a drug he had forgotten about, a court was told.
Wayne Dunne claimed he had been given the amphetamine when he was drunk.
The 49-year-old, of Nene Court, pleaded guilty to possession of the amphetamine at Spalding Police Station.
Paul Wood, prosecuting at Boston Magistrates’ Court on Wednesday, said: “He found himself in the company of police on February 14.
“He was searched and they found one small quantity of amphetamine entirely consistent with personal use.
“He said its presence there had entirely slipped his mind.”
In mitigation, Dunne said: “I had it in my possession because at the time I was slightly drunk and someone gave it to me. I put it in my pocket and completely forgot it was there.”
He was fined £40 and ordered to pay £101 in costs and victim surcharge.