Lopi sweaters can be quite sensitive to washing and should only be washed by hand. A few washing machines have very good wool programs (mine actually does) but I still wouldn't risk it.
My best method for washing goes like this:
- Fill a tub with lukewarm water and a nice smelling shampoo (yes just your regular hair shampoo) and soak your sweater in it.
- Gently squeeze and swirl the sweater around.
- Remove the water and fill the tub again with clean water and conditioner (yes, again just your regular conditioner).
- Gently squeeze and swirl the sweater around for a few minutes.
- Repeat step 4 and 5 if the water is dirty until it becomes clean.
- Squeeze most of the water from the sweater and put it in the washing machine for a slow spin for a few minutes. You can skip this step but drying time will be longer.
- Lay the sweater on a towel to dry.
Most lopi sweaters don't need washing that often and sometimes it's enough to just "freshen" them outside.