I bought myself a dragon kit from 95 and the decals are yellowed and a bit wrinkeld will that cause any problems with the finished models?
Simple yellowing shouldn’t be a problem, as you can put the sheet (design outwards) in a window and the sunlight will fade the yellowing away. (This may take a week or two)
The wrinkling is more of a worry. If it’s simply from the sheet being bent or creased it shouldn’t be a major problem. However, if the designs are bubbled or lifting from the sheet, it may indicate that the sheet has suffered moisture/water damage. If this is the case, they may not be usable.
If they haven’t been water damaged, decals which are that old may have a tendency to crack or break up when you dip them in water. As a precaution, it may be wise to give them a coat of sealer, such as Microscale’s Liquid Decal Film.
Depending on the vehicle, there may be aftermarket decals available which can offer a greater range of colouring options.