I go the route of small zipper bags for those things that need it The rest I can dry out. At local fairs and flea markets there is usually one or more dealers of knick knacks that sell assorted sizes of the Zip Loc Type baggies. From about 1 inch square These are great for a half dozen to a dozen coated cotton balls. Also keeps the kit clean. There are 2x2's 2x3's 2x4's etc. to about 6x6's. You get about a hundred for a couple of bucks. As the size increases the quantity goes down to keep the price per bundle about the same. Many places use them as small parts bags. For $20 you could probably get a lifetime supply of assorted sizes if you can find one of these dealers.

These things won't stand up to being stepped on or much of anything else. But they will keep things that need to stay dry in a kit dry. Especially if it is a quick or shallow dip.They keep my vonerable items dry even if the kit is soaked through. If you are into scuba they make specialty products for that.

For the phone I have no idea as I don't own one.