Memory leaking when placing pins

I have a SQLite database that has my label names and the lat & long, I am using a while db reader to get the name, lat and long from the database, with each iteration I am calling the method below to put the pins on the map.

I clear the layer and cycle through the 100+ records and rewrite the pins every 20 seconds, but I am bleeding memory with each cycle …maybe 250kb but it adds up over time…clearly I am not handling this correctly…

Any guidance would be appreciated.

public void mapPins(string callLabel, double gridLat, double gridLong)
var places = new[]

            new { Lat = gridLat, Lng = gridLong, Name = callLabel },

        //151N - 33.5

        // it's default setting but just in casevar gs = new GlobalSettings() {AllowLayersWithoutProjections = true};

        var sf = new Shapefile();

        // use empty string to create in-memory shapefile
        sf.CreateNewWithShapeID("", ShpfileType.SHP_POINT);
        int fieldIndex = sf.EditAddField("Name", FieldType.STRING_FIELD, 0, 20);
            foreach (var place in places)

            // convert our degrees to meters in map projection
            double projX = 0.0, projY = 0.0;
            axMap1.DegreesToProj(place.Lng, place.Lat, ref projX, ref projY);

            // create shapes for each location
            var shape = new Shape();
            shape.AddPoint(projX, projY);

            // add it to shapefile along with name
            int shapeIndex = sf.EditAddShape(shape);
            sf.EditCellValue(fieldIndex, shapeIndex, place.Name);
        sf.Labels.Generate("[Name]", tkLabelPositioning.lpCenter, true);
        sf.Labels.AvoidCollisions = false;
        sf.Labels.FontSize = 6;
        layerHandle = axMap1.AddLayer(sf, true);