I have recently got back into collecting Action Force models after a brief break away of about 20 years

I dug out my some old figures and have picked up a few on eBay, but I think they need a bit of a clean to tidy them up as they are a bit grubby and dirty from their battles.
I was hoping the collective wisdom here might be able to suggest how best to do this without risking the paint work or decals on the figures.
I tried to do a few searched on the forums and saw wet wipes being suggested. I had thought that a bit of warm soapy water and a soft brush might be best, but I would love to hear your thoughts. just dont want to damage them. So how can I get my Baron Ironblood whiter then white again?
Thanks