70% DMSO isn't that bad. Some people use 100% DMSO transdermals and yea you will prolly get some rashes but if you rotate every application you minimize the risk. You prolly can't apply 100% DMSO for very long before you eventually get rashes.
I recall a guy from the old GotFina board doing a transdermal fina using 100% DMSO and was able to run it for about 4 weeks before quitting due to rashes. He claimed that he made some nice gains too.