I overwinter every year, but grow in pots. IMO the best thing to do is to dig them up but then wash off as much soil as possible before potting them. This will help eliminate many (but not necessarily all) eggs that may be hiding in the soil. Be sure to use potting soil and not garden soil when potting them. Will the plants go into shock from this? Possibly. Every time I repot I give plants a shot of starter fertilizer, as this helps minimize or even eliminate the shock. Will spraying them down with dish soap and water help? It will eliminate any adult and larval-stage aphids, but it won't do anything to eggs. Your best bet is to have a resource handy for ordering ladybugs if you find aphids once you bring them inside. However, if ladybugs won't be available to you, keep a constant eye out for them. The minute you notice any aphids, start an all-out war. You can use dishsoap and water or insecticidal soap, but Neem seems to be more effective (though you may not want to spray that inside.) If you use a soap solution, be sure to spray every day and keep spraying every day even after you think the aphids are gone. You need to get the newly-hatched larvae before they can start to reproduce - and they do reproduce at an incredible rate. I recommend continuing to spray for at least 2 weeks after you think they're all gone - ideally twice a day, though that's not practical for some.