If you aren't sure whether najis drops have splashed onto the clothes, then those clothes will still be pak; just because there is a possibility that najis drops have reached the clothes doesn’t make them najis. If you are sure that najis drops have reached the clothes though, if they are devoid of najis substance (eyn najis), you can put them in the machine and if water from the hose that is attached to city water pipelines reaches everywhere of the machine and clothes, and the machine is turned on so that the clothes are spun and the water is drained, the clothes will become pak. Of course, in the cases that the clothes have to be washed twice, like when clothing becomes najis with urine, you must take out or turn off the hose after some water has come out of it, and once again turn it on so that they are washed twice.