This achievement is story relevant and can't be missed.
*** Spoiler - click to reveal ***
In the present, find a dime in the pay-phone in the starting room. After you got the keys from the door in the room with the sleeping conventioneer exchange the keys for the crowbar with the thief in front of the house who tries to break into the car.
You can get if you haven't it already there.
With the crowbar, get the dime that is stuck on the floor with gum. Use the dime in the gum, and Bernard will "clean" it.
Go back to the room with the sleeping conventioneer and put both dimes in the tickle finger coin slot to the right of the TV.
Get the sweater from the bed and head outside.
Use the crowbar on the vending machine and pick up all coins.
Go down to the washing room past the diner and put the wet sweater in the dryer. Insert the stacks of coins into the dryer.
In the future, go to the washing room with Laverne and get the sweater.