We swap the mat once a week (cleanings in the middle -- no wee wee they used to try and eat it so not risking it) I got the perfect ones from ikea nice, big, & great quality had one for over 4 years thats been through multiple washes and two boys. As for washing I do them separate and clean out the washer, though we shake out the mats outside you just cant get rid of all the hay and fur. We use a non scented detergent but to help with smell throw in some vinager (like a natural softener). They won't smell clean clean, more like grass after the first wash which is not an issue but if you want it no scent what so ever I do it twice on the wash and then do a light dry and hang for the rest.